Recent Advances in Granite Ground Stone Studies in the Eastern Maya Lowlands

Abstract

Used for common daily tasks, ground stone tools were vital to the functioning of pre-Columbian Maya households. Yet as an artifact class, ground stone has historically received little archaeological attention. Throughout the Eastern Maya Lowlands, ground stone tools were made of a variety of materials although granite was a preferred raw material. Granite is geographically restricted to three plutons, making it a prime candidate for geochemical sourcing studies. Fueled in part by advances in compositional techniques, as well as by new finds from traditional field archaeology, interest in the topic has blossomed over the past decade. This Compact Section explores many facets of the pre-Columbian Maya granite ground stone economy, from raw material acquisition to end of life discard, with the goal of disseminating the work of ongoing research projects. Ultimately, we aim to encourage more research on ground stone tools in general and granite in particular in Maya archaeology. Like other sister categories of artifacts, ground stone deserves requisite research attention to answer questions about where and how raw materials were acquired, how these objects were crafted, what distribution networks looked like, how they signify broader social meanings, and beyond.

Resumen

Utilizadas para tareas cotidianas comunes, las herramientas de piedra molida eran vitales para el funcionamiento de los hogares Mayas Precolombianos. El conjunto de mano/metate, por ejemplo, sigue siendo una característica común de muchas cocinas Mayas descendientes, y los datos etnohistóricos y arqueológicos indican que su importancia era mucho mayor en la era anterior a las piedras de moler eléctricas. Sin embargo, como clase de artefacto, la “piedra molida” ha recibido históricamente menos atención arqueológica a pesar de su potencial analítico e interpretativo. Los avances en las técnicas de composición, así como los nuevos hallazgos de la arqueología de campo tradicional en las tierras bajas Mayas orientales en los últimos 10–15 años, han alimentado un renovado interés en la categoría de artefactos. En esta Compact Section, nos centramos específicamente en el granito como materia prima para la producción de piedra molida. Si bien se han recuperado herramientas de granito y elementos arquitectónicos en sitios arqueológicos de toda la región, su distribución está restringida geográficamente a tres plutones en las montañas mayas de Belice, lo que lo convierte en un candidato principal para la investigación utilizando técnicas de caracterización.

El trabajo de procedencia de Tibbits (2016; véase también Tibbits et al. 2022) ha demostrado que el granito puede obtenerse de forma fiable en su plutón mediante fluorescencia de rayos X (XRF) portátil y de dispersión de energía. Desarrollos metodológicos como estos han permitido a los investigadores de toda la región hacer preguntas más amplias sobre este material y los objetos de piedra molida hechos de él. Esta Compact Section explora muchas facetas de la economía de la piedra molida de granito maya precolombina, desde la adquisición de materia prima hasta el descarte al final de su vida útil, con el objetivo de difundir el trabajo de los proyectos de investigación en curso. En última instancia, nuestro objetivo es fomentar más investigaciones sobre artefactos de piedra molida en general, y de granito en particular, en arqueología Maya. Al igual que otras categorías hermanas de artefactos, la piedra molida merece la atención necesaria para responder a preguntas sobre dónde y cómo se adquirieron las materias primas, cómo se fabricaron estos objetos, cómo eran las redes de distribución, cómo significan significados sociales más amplios y más allá.

The case for ground stone tools

Ground stone artifacts are ubiquitous throughout ancient Mesoamerica, yet they are often understudied by archaeologists beyond simple counts, weights, raw material, and form. As Martin Biskowski (2008:144) lamented,

the category “ground stone” generally lacks cohesion and in practice is often defined negatively as any artifact which is neither ceramic nor obsidian and thus not to be rebagged with those materials. Consequently, ground stone analysis frequently is the analysis of the leftover items which often have little in common with each other.

This general lack of analytical interest may also be related to the commonality of such tools in the houses of many living and recent descendant Maya communities. However, in many ways ground stone tools (GST) in Mesoamerica represent a tangible link between present and past practices (Searcy 2011:1), allowing ethnoarchaeologists to observe first-hand how such tools are acquired and used, and what their broader significances are today, providing strong analogies for interpreting the past.

The articles presented in this Compact Section of Ancient Mesoamerica are the result of an organized session led by Jon Spenard during the 87th meetings of the Society for American Archaeology in Portland, Oregon. The original call for proposals asked participants to consider the role of granite GST in ancient Maya society, specifically focusing on how granite was extracted, used, and distributed throughout the landscape of the Eastern Maya Lowlands. The articles presented here approach GST from various points along the life cycle of the tool category, from quarrying of raw granite (Spenard et al., this section) and production of the classic mano and metate set (King and Powis, this section), to the significance of GST distribution, use, and discard patterns for socioeconomic development (Brouwer Burg et al., this section; Peuramaki-Brown et al., this section). They are all related in that handheld, portable X-ray fluorescence (pXRF) has been used to approximate the provenience of the granite found in the artifact assemblages of these separate projects: the Stann Creek Regional Archaeological Project (SCRAP), the Belize River East Archaeological Project (BREA), the Rio Frio Regional Archaeological Project (RiFRAP), and the Pacbitun Regional Archaeological Project (PRAP; Figure 1). Two summative articles conclude this Compact Section, providing a long-lensed view of GST studies in the Eastern Maya Lowlands (Graham, this section) and the potentialities of studying GST from a broader, hemispheric perspective (Schneider, this section).

Figure 1. Eastern Maya Lowlands showing archaeological projects and sites mentioned in text. CCB = Cockscomb Basin, HBR = Hummingbird Ridge, MPR = Mountain Pine Ridge.

Before getting into the specifics, however, we wish to situate our interest in granite GST, and provide some key definitions. Stone artifacts categorized as “groundstone,” “ground stone,” or “grinding stones” comprise a broad array of objects, all of which have either been worked or modified through the actions of pounding, pecking, grinding, polishing, and abrading (Adams 2002:1), and/or are used in such a manner once complete. We recognize the significance in using the technological term “ground stone” rather than the functional term “grinding stone” to describe these specimen. Most of these objects were produced through processes other than grinding, namely pecking, but many of them were used for grinding and pulverizing activities. Nevertheless, since “ground stone” is the term most commonly used in analytical conversations, and following the foundational work of Jenny L. Adams [2002], we retain its use here. We also consider, to a lesser degree, stone that was used to facilitate or accomplish the movements and tasks described above (e.g., a natural stone outcrop used as an anvil or grinding basin; Hayden 1987; Rowan and Ebeling 2008; Spenard et al., this section) or stone that was shaped through these processes and used in building construction (although we recognize that the latter were probably not considered in the same functional category as tools; see Peuramaki-Brown and colleagues, this section).

GST are identified by various characteristics, including raw material type, morphology, surface treatment, and occasionally, the traces of processed residues that remain on their surfaces (e.g., Cristiani and Zupancich 2021; Dubreuil et al. 2015). Unlike chipped stone implements, which require rock that breaks conchoidally (e.g., obsidian, chert, quartz), GST require raw material that crumbles or breaks down around phenocrysts or grain particles during the grinding portion of manufacture (e.g., igneous rock like granite, basalt, and rhyolite, or sedimentary rock like sandstone or limestone; Andrefsky 2005:47–59). Production of GST requires both percussive and grinding phases, as Spenard and colleagues discuss in their contribution to this Compact Section. Percussion flaking was employed during the initial stages of reduction after the raw material was extracted, a strategy also documented in northern Mexico (Searcy and Pitezel 2018), and in the U.S. Southwest and California (Schneider 1993a, 1993b, 1996).

The most prevalent GST type from the Mesoamerican archaeological record is the mano-metate set; the metate is a large netherstone upon which substances to be ground are placed and then worked with the hand stone or “mano” (Adams 2002:99). Both components are required to accomplish the grinding task (Adams 1999:481) and ethnographic research throughout Mesoamerica indicates that manos and metates are often produced as matched sets, meaning a mano is constructed to fit a specific metate, and vice versa (Cook 1982:198; Hayden 1987; Searcy 2011). Every household unit would require some form of GST to process milled food products, and perhaps another to grind non-food materials (e.g., lime for washing, pigments for paints; Searcy 2011; Graham, this section). Evidence suggests that in addition to everyday tasks, these tools were also vital to ritual practices (Biskowski 1997, 2000, 2008; Clark 1988; Cook 1982; Hayden 1987; Searcy 2011). Yet, they have regularly been overlooked as subjects of scholarly inquiry, this perhaps being related to their ubiquity in the ethnographic present and archaeological past, and/or to their bulky proportions making them difficult to curate in archaeological labs. While the work of a handful of scholars has attempted to rectify the situation (e.g., Adams 2002; de Chantal 2019; Clark 1988; Hansen et al. 2020; Hayden 1987; Jaime-Riveron 2016; Pritchard-Parker and Torres 1998; Rodríguez-Yc 2013, 2018; Rowan and Ebeling 2008; Ruiz Aguilar 2005, 2007; Searcy 2011; VanPool and Leonard 2002)—especially with the application of newer, non-destructive analytical tools like pXRF—there is still much theoretical and methodological development needed to explore the chaîne opératoire of GST within the Eastern Maya Lowlands and beyond.

Below, we describe why we have chosen as a group to focus on granite GST in this Compact Section and set the geological scene for the research discussed herein. Next, we evaluate recent and ongoing work focused on expanding understandings of ground stone extraction, production, exchange, use, and meaning, finishing up with an overview of the research articles contained in this section, and identifying promising areas for future research.

Why granite?

Ancient Maya people made GST from a variety of stone, from the locally available to material that came from far afield (e.g., Brouwer Burg et al. 2021:Table 1; Graham 1987; Halperin et al. 2020). Though studies indicate that raw stone preferences changed over time (e.g. Halperin et al. 2020), an exploration of temporal trends in raw stone usage for GST is beyond the scope of the current Compact Section; however, we stress that this is a research avenue that is yielding important insights, especially with novel, portable instruments like handheld XRF. At sites throughout the Eastern Maya Lowlands, GST made from limestone, quartzite, granite, and basalt are commonly reported (Tibbits 2016). Across northern Guatemala, limestone and quartzite are the most reported materials used for GST, but at Tikal and Yaxha, granite objects make up approximately 7 percent and 19 percent of the assemblages respectively (Halperin et al. 2020:Table 3). At Ucanal, granite GST make up approximately 35 percent of the Late Classic assemblage (Halperin et al. 2020:Table 2). Though percentages are unreported, granite GST have been recovered from Calakmul (Gunn et al. 2020:9–11, 117) and Nakbe, the latter from Middle and Late Preclassic period contexts (Hansen et al. 2020:329–331).

In northern Belize, local sedimentary rock (e.g., limestone) was commonly used for GST, followed by granite and other non-local materials like basalt. In the Upper Belize Valley, granite originating in the Maya Mountains, mostly from the nearby Mountain Pine Ridge source, was commonly used although tools were also made from locally available limestone, sandstone and non-local basalt (see Brouwer Burg et al. 2021). Notably, granite from the Mountain Pine Ridge was the most represented non-local material used for GST recovered in the middle Belize Valley, although local stone was also used (see Brouwer Burg et al., this section). In the Sibun Valley and Southern Belize, non-local basalt was commonly used, along with granite and (in the latter case) other local volcanic and volcaniclastic rocks (see e.g., Abramiuk and Meurer 2006). Unsurprisingly, granite was very commonly used for GST in the Maya Mountains but not to the exclusion of other locally available stone like quartzite and limestone (see Chase and Chase 2005, 2006, 2008, 2012, 2015, 2016, 2017; Chase et al. 2019). Even some non-local basalt was brought into the Maya Mountains, despite the local abundance of granite.

Beyond the accessibility of rock, there are various other qualities and characteristics of stone that ethnoarchaeologists and ethnohistorians have determined likely impacted the choice of raw material, which we describe below. For large and heavy tools like GST, however, we cannot help but ask the twin questions of how and why? Mano and metate sets often average between 13.5 and 23 kg (~30 to 50 lb; McBryde 1947:73), so how would they have been produced and, perhaps more importantly, how were they moved around the landscape in a cultural area with no domesticated pack animals? Ethnographic studies of stone workers from highland Guatemala (Nelson 1987a, 1987b; Searcy 2011) and Mexico (Cook 1982) provide some insight into the latter. While contemporary stone workers who make manos and metates (sometimes referred to as metateros) regularly use motor vehicles to transport finished products, loads of up to 45 kg (100 lb—two metates and six manos) were traditionally carried on foot by tumpline (McBryde 1947:73). Reports indicate that some individuals traveled that way to markets over 100 km distant across mountainous terrain (Searcy 2011:69–70). As to why GST were moved such distances, feeding a growing population must have been part of the answer but, as the authors in this Compact Section discuss, broader sociocultural motivators were also likely at play. Otherwise, populations would have used locally available materials rather than importing GST made from distantly sourced raw material.

Setting the geologic scene

In this section, we provide a brief overview of the geology of granite in the Maya Lowlands. We focus on the Maya Mountains as the primary source of granite for the majority of ancient Maya sites in Belize as well as in adjacent areas of Guatemala and Mexico, as noted above. We do not discount the fact that granite from other sources in the Maya highlands might also have been used but, to our knowledge, the relative lack of attention paid to GST in Maya archaeology has left such questions currently unanswerable. One of our primary aims with this Compact Section is to demonstrate the research potential of granite and non-granite GST for Maya archaeology, as well as the analytical potential of portable and non-destructive instruments such as pXRF.

The Maya Mountains, often referred to as the highlands of the Maya Lowlands, represent a region of igneous and metamorphic rocks spread across northern Guatemala and central Belize (Figure 1). It is not the only source of granite occurring in the traditional territory of the ancient Maya—there is also the Rabinal granite source (Ortega-Obregón et al. 2008) and the Altos Cuchumatanes (Anderson et al. 1973; Solari et al. 2010, 2013) in the highlands of Guatemala, as well as scattered outcrops in the central cordillera of Honduras (Mills et al. 1967). Granites have also been reported in the Sierra Madre Mountains in Mexico (Sanchez Montes de Oca 1978; Waibel 1946).

Granite in the Maya Mountains is surrounded by a metamorphic areole comprised of early Paleozoic materials (Bateson and Hall 1977; Dixon 1956). Petrographically, its metamorphic rocks are largely quartzite, slate, and phyllite, with some gneiss (Bateson and Hall 1977; Dixon 1956; Weber et al. 2012). Outside the Maya Mountains, the Eastern Lowlands’ geology is dominated by Paleozoic sedimentary deposits including limestone and sandstone with locally occurring veins of chert. These sedimentary resources, including chert, limestone, and sandstone, were used extensively for both ground and chipped stone tools.

The degree to which local and non-local materials were utilized over space and time by the ancient Maya is of interest to archaeology; only recently have geochemical techniques like pXRF allowed researchers to conduct provenience studies of stone artifacts without compromising the objects themselves. There are three characteristics of granite that make it an ideal candidate for unlocking questions about production, exchange, use, and meaning: 1) it was a popular rock type used widely by the ancient Maya for GST production; 2) it is geographically restricted in the Eastern Lowlands to the Maya Mountains; and 3) different outcrops within the Maya Mountains have distinct geochemical signatures that can be differentiated by XRF and other provenience analyses (Tibbits 2016).

Granite forms three distinct plutons within the Maya Mountains: Mountain Pine Ridge, Hummingbird Ridge, and Cockscomb Basin (Dixon 1956; Ower 1928). The plutons range in composition from granite to tonalite with quartz porphyries in all plutons and dacitic intrusions reported in Mountain Pine Ridge and Hummingbird Ridge (e.g., Bateson and Hall 1977; Dixon 1956; Jackson et al. 1995; Ower 1928; Shipley 1978; Weber et al. 2012). Here, we describe the petrographic and radiometric differences of the plutons to better situate the following conversations of granite GST production, exchange, use, and meaning.

Cockscomb Basin granite is the least studied of the three plutons, largely related to the difficulty in physically accessing it to obtain samples today. The outcrop lies within a heavily forested, mountainous region of Belize that is protected as part of the Cockscomb Wildlife Sanctuary and Jaguar Preserve. No roads penetrate the wilderness regions. The granite from this source is predominantly light in color and composed of two-micas with plagioclase feldspar and quartz as the dominant minerals (Bateson and Hall 1977). Potassium feldspar is also present but in lower proportions than plagioclase. Biotite is the dominant mica, though muscovite also occurs in some outcrops (Bateson and Hall 1977; Dixon 1956).

Hummingbird Ridge granite is more readily accessible via the Hummingbird and Coastal highways of Belize and, consequently, it is relatively well studied. The dominant minerals are plagioclase feldspar and quartz with more potassium feldspar than is reported for the Cockscomb Basin granite. Muscovite mica is more prevalent than biotite mica although ratios of the two vary within the pluton (Bateson and Hall 1977; Dixon 1956; Tibbits 2016). Visually discerning Hummingbird Ridge from Cockscomb Basin granite is difficult as both are white to gray with small dark crystals.

Mountain Pine Ridge granite exhibits a wide range of petrographic variation (Jackson et al. 1995). It is most commonly pinkish in color due to high proportions of potassium feldspar. This contrasts with the predominantly white coloration of granites from the Cockscomb Basin and Hummingbird Ridge (though it is worth noting that Cornec 2015 mentions the possibility of pink granite in the Cockscomb Basin). The proportions of micas in the Mountain Pine Ridge are lower than in granites from the other two plutons (Bateson and Hall 1977; Dixon 1956; Jackson et al. 1995).

To better understand the chemical differences between the three granite plutons, geologists have attempted to reconstruct the timing and process of their formation. Using U-Pb zircon dating, researchers found that Mountain Pine Ridge granite was most recently formed, with an emplacement age of 400 ± 8 Ma (i.e., the Devonian Period; Martens et al. 2010; Steiner and Walker 1996; Weber et al. 2012); the Hummingbird Ridge granite formed somewhat earlier within the same period, between 408 and 417 Ma (Weber et al. 2012). Tibbits (2016) collected granite directly from the Cockscomb Basin and processed hand samples to obtain zircons, which were analyzed for U-Th-Pb isotopes and trace elements using sensitive high-resolution ion microprobe-reverse geometry (SHRIMP-RG) at the Stanford–U.S. Geological Survey Micro-Analysis Center at Stanford University. The results of the analysis yielded a ²⁰⁶Pb/²³⁸U weighted mean age of 423 ± 4 Ma for the crystallization of the Cockscomb Basin pluton (Figure 2; Tibbits 2016). This age is consistent with the established ages of Late Devonian to Early Silurian for the Hummingbird Ridge (408–417 Ma) and the Mountain Pine Ridge plutons (400–418 Ma; Steiner and Walker 1996; Weber et al. 2012).

Figure 2. Comparison of published ages for the granite plutons in the Maya Mountains. MPR = Mountain Pine Ridge, HBR = Hummingbird Ridge.

The recently obtained date range for the Cockscomb Basin presented here refines the temporal framework of the Maya Mountains and solidifies the age of the Cockscomb Basin granite. We submit that there were at least two major pulses of magmatism that formed the plutonic portions of the Maya Mountains: between 420 and 415 Ma, forming the Cockscomb Basin and Hummingbird Ridge plutons; and again between 408 and 400 Ma, resulting in the Mountain Pine Ridge pluton (see overlap in error bars in Figure 2). Further research into the timing and tempo of the magmatic pulses will have important implications for refining the relationships between the geochemical signatures of the Maya Mountain granite plutons.

We now turn our attention to what can be learned from GST about broader sociocultural processes, with a focus on extraction and production, exchange, use, and meaning. As called for by Wright (2008:130), it is imperative that GST as an artifact category be considered more holistically, “in terms of whole systems of organization of such artifacts, from raw material procurement to final abandonment.” If we are to fully understand the importance of GST in past Maya cultures, not only must we give this tool class requisite attention, but we must also refrain from preferencing GST over non-tools (e.g., extraction and production debris, preforms, and failed tools) in order to gain a fuller understanding of the chaînes opératoires (see discussion in Schneider, this section).

Provenience studies

At the core of most GST studies is the basic question: where did these stones come from? The search for meaning within the tools, questions surrounding their movement and exchange, and even discussions concerning mining and production methods cannot be explored fully without first knowing where the parent rock originated (Shott 2021). A variety of chemical composition studies have been applied to archaeological assemblages in the last 20+ years, including X-ray diffraction (XRD), lab-based XRF, pXRF, inductively coupled plasma mass spectrometry (ICP-MS), laser-induced breakdown spectroscopy (LIBS), and neutron activation analysis (NAA). Methods for sourcing lithic tools vary by rock type and available equipment. Some rock types are more amenable to specific sourcing techniques given their structure or composition. For example, much research has focused on sourcing obsidian, which makes it an excellent candidate for XRF analysis given its homogenous composition (e.g., Moholy-Nagy et al. 2013; Nazaroff et al. 2010; Simmons et al. 2023; Stroth et al. 2019).

Heterogenous rock, such as granite, is more difficult to source using point-and-shoot technologies although robust, lab-tested methods have been developed. Tibbits (2016; Tibbits et al. 2022) developed a method for differentiating between the Maya Mountain granites that requires a minimum of five randomly selected datapoints from a single specimen, which are then averaged to generate a bulk geochemical signature. That process has allowed for XRF sourcing of granite GST with reasonable success at identifying a source pluton. Currently, it is not possible with XRF to differentiate discrete signatures from within plutons.

The benefits and applications of XRF to provenience studies have been well demonstrated for fine-grained (aphanitic) rocks, such as basalt and obsidian (e.g. Biskowski 1997; Frahm 2012, 2013, 2024; Frahm and Doonan 2013; Grave et al. 2012; Nazaroff et al. 2010; Williams-Thorpe et al. 1999). The ability to use XRF has also been proven on relatively finer-grained phaneritic and porphyritic rocks, such as dacite (Greenough et al. 2004). Provenience studies have the potential to open new avenues of inquiry into GST. With the expansion of field-based XRF and other non-destructive or minimally destructive techniques, questions regarding source location, transportation, economics, and social innerworkings are being explored (e.g., Greenough et al. 2004; Palumbo et al. 2015; Williams-Thorpe et al. 2003). We next consider how these analyses are helping to unlock questions about the extraction, production, use, and meaning of GST in the Eastern Maya Lowlands.

Extraction and production

While the quarrying of raw material for GST production has received some attention in other parts of the world (e.g., western North America [Kolvet et al. 2000; Schneider 1993a, 1996, 2008; Schneider and LaPorta 2008; Schneider et al. 1995]; Southwest Asia/North Africa [Amit et al. 2008; Harrell and Brown 2008; Peacock 1997]), only sporadic research has focused on understanding the extraction of rock for GST production in Mesoamerica (e.g., Cook 1973, 1982; Rodríguez-Yc 2013; Searcy and Pitezel 2018; Williams and Heizer 1965). And, while granite GSTs have been found throughout the Eastern Maya Lowlands over the last century of archaeological research, only in the last two years has concrete evidence of ancient Maya quarrying been established in the Mountain Pine Ridge region of the Maya Mountains (see Spenard et al., this section). Furthermore, while the extraction and production of basalt by ethnographically documented Maya groups has been observed (Dary and Esquivel 1991; Garcia Chávez et al. 2002; Hayden 1987; Searcy 2011; Searcy and Pitezel 2018), only one in-depth study of granite extraction and production has been undertaken in contemporary Mesoamerica (Cook 1982) and thus the bulk of our inferences are based upon data gathered from extraction of the former rather than the latter.

A general sequence of production is followed by most ethnographically observed stone workers in Mesoamerica. Large stone boulders are pried or blasted out of the subsurface. Next, blocks are removed from the boulder and taken to a secondary roughing-out area. Initial shaping is conducted at the extraction site and roughed-out forms are typically ferried back to workshop spaces adjacent to homes, located 1–10 km distant (Hayden 1987:21–22; Searcy 2011:34–36; note: a similar spatial relationship has been observed by King and Powis, this section).

The second phase of the process—shaping and finishing—is conducted in home workshops. The GST is finished through fine pecking and abrasion of the surface, a process that produces large quantities of micro-debitage (Nelson 1987a). Searcy (2011) and others (Cook 1982; Hayden 1987) emphasize that a variety of tools are used in each step, from long batons and sledges, to varying sizes of metal picks.

As with the technical organization of many quarrying activities, extraction is typically undertaken by a set of individuals who may be patrilineal kin (Cook 1982:159; Searcy 2011:64) or part of a craft guild (Hirth 2008:444; Marcus 2012). The skills necessary for quarrying and GST production appear to be bundled and passed primarily through apprenticeships, with younger novices learning by watching and experiential practice. Searcy (2011:50) notes that younger stone workers make the easier mano forms as they learn the intricacies of producing the more difficult metate forms.

Other important topics to consider in the extraction and production of GST involve the selection and perceived quality of the stone used. Both Hayden (1987) and Searcy (2011:54–56) found that three key characteristics were sought by stone workers as well as the consumers of ground stone: 1) density of vesicles (holes in the stone created by gas bubbles during emplacement); 2) color (although these are not preferences for literal colors but rather associations of quality with color); and 3) presence of flaws or weaknesses in the stone.

Exchange

We could consider GST similarly to the way Drennan (1984a) approaches ceramics—they are also heavy, unwieldy, and sometimes breakable, rendering them less than ideal for transport over long distances. However, the geographically restricted nature of granite in Mesoamerica, and analytical techniques permitting researchers to connect geochemical fingerprints between sources and artifacts, is facilitating investigation of a broader range of questions surrounding the exchange of GST.

Granite is a heavy rock; mano-metate (2007)sets made from the material can weigh on average about 23 kg (or 50 lb). McBryde (1947:73) estimated that a standard load for an individual is about 45 kg (100 lb), consisting of two metates and six manos. In his work on transport costs, Drennan (1984b:105) assumes a standard bearer load of 30 kg; he argues that water transport by canoe, raft, or dory presented a more energy efficient mode of transport. The use of canoes by living and recent Maya groups has been observed as a widespread phenomenon, and Drennan (1984b:106) works from the premise that a four-paddle dugout canoe could easily manage a one-ton load. Schneider and colleagues carried out a replication experiment for water transport of stone tools and found that 113–181 kg of stone cargo and human paddlers could move 1.6 km per hour in a small (3 m long) tule raft in 50 cm of water (Schneider and LaPorta 2008:31).

As Brouwer Burg and colleagues (this section) discuss, there are various models of exchange that were likely at work simultaneously in the ancient Maya world. Their inferences are based in part on observations made of living Maya groups. Mano-metate sets are most often purchased at local markets by consumers following a generalized market-based exchange model (Cook 1982; McBryde 1947:81–83; Searcy 2011:66–71). Occasionally, middlemen will purchase metates wholesale from mano-metate makers and then resell them to retailers or in their own stalls at markets (Cook 1982:253–254; Searcy 2011:69). Moreover, mano-metate sets will often be gifted directly to newlyweds or as a housewarming gift, a type of gift exchange. Unlike consumable commodities, GST cannot be further subdivided and thus do not make good candidates for traditional down-the-line exchange models. However, GST seem to be key components of intergenerational exchange systems, especially among women. Searcy (2011:72) notes that 53 percent of the metates he studied were passed down among generations, with 88 percent of those sets being given to daughters. Additionally, GST are often repurposed for a variety of different practical tasks, from those similar to the originally intended use of grinding, to serving as hammerstones, structural fill, and even table supports (for discussion of GST life histories, use, and recycling, see Basgall 2008; Fullagar et al. 2008; Hayden 1987:191; Kadowaki 2008; Searcy 2011:98–100; Wright 2008).

Use and meaning

The tool category of ground stone is typically associated with utilitarian and domestic uses; however, ethnographic studies, iconographic depictions, and ethnoarchaeological research focused on understanding the life histories of GST indicate that these objects were used in a much broader array of activities. Relatedly, while the mano-metate set may appear to supply inferential information about female-gendered tasks in the home, new analysis techniques and theoretical developments are challenging researchers to think more deeply and widely about the significances of these tools. We outline these research initiatives below.

The ethnographic evidence from Mesoamerica is helpful in providing correlates for how ancient GST might have been used, and archaeological material studies focused on extracting microbotanical residues from GST, such as phytoliths and starch grains, have bolstered this data (Cagnato 2018; Piperno and Holst 1998). The mano-metate set is undoubtedly one of the most important tools in the home used to produce a) masa flour, the dietary foundation in this part of the world; b) other foods like coffee, cacao, chili, garlic, etc. (Searcy 2011:76); and c) other substances including pigments, spices, and salt (Hayden 1987:188). And, even with today’s modern conveniences such as gas-powered metal mills available in many towns, it is remarkable how many Maya women still report using their mano-metate sets daily: among the Q’eqchi’, more than 90 percent of women report using their sets multiple times a day (Searcy 2011:Figure 4.6). Over 50 percent of the Poqomam Maya report using their sets multiple times a day, and over 30 percent report using them at least once a day, for a total of 80 percent in daily usage. The K’iche’ Maya use their mano-metate sets less frequently with about 45 percent reporting rare usage, 25 percent weekly, 25 percent daily, and about 5 percent multiple times a day. Nevertheless, the K’iche’ Maya keep old GST around in case of electrical outages (not uncommon), or to give automated-mill-ground flour a quick final grind (Searcy 2011:76).

Similar to the way in which adolescent males learn how to extract and form GST, adolescent Maya girls may also learn to become efficient metate users by watching and coaching from their mothers (see Isaac 1986:16). While observing experienced Hopi women making efficient use of their GST, Adams (2002:68) noted a kind of embodied knowledge in which the body (rather than the mind) led the process. As with other types of embodied knowledge, this information cannot be learned through verbal description alone; the physical practice of achieving the desired result must be experienced and honed by the doer (see “knowledge in the hands” described by Merleau-Ponty 2013 [1962]; also Tanaka 2011). We assume that ancient Maya women learned to use mano-metate sets in this way. While there is no direct evidence yet to support this assumption from the archaeological record, a scene on page 60 of the Codex Mendoza shows an Aztec mother instructing her daughter in the appropriate body movements and placements for efficient grinding (Searcy 2011:84–85, Figure 4.7). Other important knowledge that was likely passed down between GST users involved the quality of the stone used and methods for resurfacing a metate to improve grinding efficiency (usually achieved through pecking to increase roughness).

The choice of stone to use in the production of a GST is culturally coded. While raw material choice is something that modern-day analyzers might distill down to physical attributes like surface texture, hardness, fracturing properties, and accessibility, Carter (2008:67) reminds us that “ancient choices may have been structured by quite different notions of appropriateness, involving the stone’s more esoteric and non-mechanical qualities, such as color, smell, specific place of origin and its associated metaphysical properties” (see also McKenzie 1983) or “the procurer’s rights of access, based on group affiliation, age, and/or gender” (Carter 2008:67; cf. Hampton 1999:227–228; Torrence 1986:52–57). All of these characteristics are bound up in the social significance of ground stone.

Probing beyond the quotidian uses of the mano-metate set in Mesoamerica, ethnographers have demonstrated the many varied meanings of GST. For example, the sets embody a gender complementarity that runs throughout much of living Maya social life: while men are responsible for the extraction, production, and often exchange of mano-metate sets, “once they have been used by a woman, a man should not touch them out of respect for the stone and the woman” (Searcy 2011:93). To reify the boundaries of appropriate gendered tool use—reflecting the gendered division of labor—there are culturally constructed taboos or awas associated with men who encounter mano-metate sets after their use-life begins. The resulting curse ensures the man will only produce offspring of the opposite gender, which provides significant insight into the value of women in society. It is important to highlight that these gender divisions are further codified in the Popol Vuh, in which the female creator deity, Xmucane, ground the corn that would be mixed with water to form the first four male deities on a metate (Tedlock 1996:43–44). The above research indicates that GST sets may have been seen in some instances as object-persons with the agency to interact with humans in certain ways.

The idea that stone was alive and had agency is common in Mesoamerican thought. Maya iconography is rife with images of living rocks of all sizes, from mountains to portable objects (Stuart 2010:288). Mountains and hills, the epitome of rocky things, were considered living entities (Stuart 1997:14) whose cave-mouths exhaled cloudy, rain-filled breath (Brady and Ashmore 1999; Taube 2001). Maya rulers are regularly depicted standing on sprouting, breathing zoomorphic mountains, commonly referred to as the “Kawac Monster” (Taylor 1978) or “Witz Monster” (Stone and Zender 2011:139, 169) on stelae, public monuments, and even the facades of structures (Andrews 1995; Fash 1991:123; Gendrop 1998; Taube 2004:79–86, 2006:154–158, 2010). The being has been referred to as the “essence of stone” (Schele et al. 1986:45–46), but it is used in reference to the cave-filled mountains and hills that make up most of the Maya region, which in the lowlands is primarily limestone.

Manos and metates are commonly reported from ritual cave sites throughout the Maya region (Bassie-Sweet 1996; Brady 1989; Halperin and Spenard 2015; Ishihara 2007; MacLeod and Puleston 1978; Morton 2015; Moyes 2005, 2006; Pendergast 1969; Peterson 2006; Prufer 2002; Slater 2014; Spenard 2006, 2014; Woodfill 2007). A unique occurrence of GST in an underground setting comes from the cavern beneath the site of Balankanche, Yucatan. There, archaeologists recorded over 250 miniature mano-metate sets and censers, the latter decorated with the face of Tlaloc, the central Mexican rain deity (Andrews 1970). Unfortunately, little overall theorizing has been done to understand the presence of GST in underground sites, except to suggest they were used for agricultural rituals, to prepare ritual food, or related to rain making. Additionally, GST recovered in cave contexts are often fragmented, which may be related to the releasing or returning of the item’s spirit to the ground, effectively ending its life cycle.

Were granite GST, especially manos and metates, imbued with life essence similar to the other rocks and minerals? Two instances of the objects depicted on vessels were identified in the online Kerr Maya Vase Database. In both cases, the tools are footed and in active use; one is gray and the other covered in black and white speckles, suggesting the items were made from basalt and granite respectively as commonly reported in archaeological literature. Stuart (2014) has recently proposed a reading of KA’ for the “bent kawak” glyph, meaning metate or grinding stone. As the colloquial name for the glyph suggests, it contains the cluster of grapes motif, a possible reference to the items being made from limestone. One of the examples presented has a zoomorphic component, a head on top of the grinding surface in the position where an accompanying mano (stylized as a human hand) rests in the other examples. Clearly, much more research into the symbolic nature of GST is required.

Organization of this compact section and future avenues for research

This Compact Section’s overall aim is to highlight some of the recent and ongoing work underway on ground stone, yet many questions remain for those interested in probing the significances of ancient Maya granite GST. These can be clustered around the themed areas we describe above. Much remains to be done to further elucidate where raw material for GST were quarried, by whom, and how. Specifically, new field research in granite-rich areas is revealing the first concrete evidence for extraction and production of these manos and metates in the Eastern Maya Lowlands. Spenard et al. (this section) describe dozens of extraction loci that were found surrounded by quarry tailings, extensive reduction debitage, discarded products, and tools for extraction and reduction at the recently identified Buffalo Hills Quarries site. To understand the scope of granite GST production within domestic workshop contexts, King and Powis (this section; see also Skaggs et al. 2020; Ward 2013) detail new data from the ancient Maya site of Pacbitun, where there was a community-wide focus on granite tool production. These two articles provide tantalizing glimpses into what could be a well-developed ground stone industry. Trajectories for future research entail problematizing elements of the production process through broader spatial surveys, and persistent questions revolve around understanding how quarrying and production work was organized in both socioeconomic and spatiotemporal levels.

While these contributions shed new light on the scale at which quarrying and production was organized in the Mountain Pine Ridge area, there is currently a dearth of information on the who, when, where, and why of granite resource management among the Hummingbird Ridge and Cockscomb Basin outcrops. The research that stands out is that currently led by Peuramaki-Brown and colleagues (this section) at the site of Alabama, where granite appears to have served as one of the staple resources that facilitated the relatively sudden rise of the town toward the end of the Late Classic (see also Peuramaki-Brown and Morton 2019). Employing a holistic view of granite use, these authors underscore the need for further research into the multiscale behavioral processes and meanings involved in resource management, which is much more than just an economic endeavor. Furthermore, their work—as a counterpoint to work in the Mountain Pine Ridge—has generated many new questions about different approaches to extraction, production, and exchange that were carried out by ancient Maya groups in the Cockscomb Basin outcrop.

The beauty (and curse) of using XRF is that it provides a neat connection between a granite source and the place where a granite GST was found. For inferential development, however, this tidy connection has proven thorny. In their contribution, Brouwer Burg and colleagues (this section) start with the provenience data (that is, granite found in the middle and lower reaches of the Belize River Watershed has been found to derive primarily from the Mountain Pine Ridge source), and then attempt to puzzle out the various mechanisms by which that granite moved and what that movement signifies. In their heuristic modeling of these questions, they pose a series of questions to cast against the material correlates of the archaeological record, questions that should occupy future researchers for years to come, including how the granite was moved and what that movement could signify about larger sociopolitical relationships and culturally held beliefs.

The last two articles in this Compact Section are intended to provide both a retrospective on ground stone studies in the Eastern Maya Lowlands and a broader comparison of the latter to the trajectories of ground stone studies in other parts of the Americas. Graham is no stranger to the geologic resources of Belize, having published in the late 1980s several articles on resource diversity and stone availability (e.g., Graham 1987; Shipley and Graham 1987). In this Compact Section, she ponders other uses granite may have satisfied, focusing on granite minerals for paints and slips. Her contribution encourages all scholars interested in this artifact category to expand thinking beyond use to the meanings behind GST more generally. In the final article, Schneider provides a history of the application of the chaîne opératoire to ground stone tool production as she considers the broader contexts in which ground stone functioned in past societies. She couches a commentary to the articles in this section within a consideration of our modern-day conceptualizations of sites, specifically the site-type “ground stone quarry.”

In addition to the two summative works included here, the four research contributions in this Compact Section represent, to our knowledge, the first time that different research projects studying the ancient Maya—some proximate and others further afield—have come together around the subject of granite ground stone in order to answer the many questions we have independently converged upon. In this manner, we are working collaboratively to understand the full life cycle, both materially and spatiotemporally, of the ancient Maya granite ground stone economy, which our collective research suggests was a more complex and widespread system than previously thought. We acknowledge that the articles contained herein are restricted spatially in their focus on Belize. It was not our intent to exclude researchers working outside of Belize on similar questions; rather, the spatial scope of these articles simply highlights where such research is primarily being carried out. We also wish to recognize that additional recent work is being conducted on ground stone outside of Belize in neighboring parts of Guatemala (e.g., de Chantal 2019; Halperin 2021; Halperin et al. 2020) and Mexico (see Jaime-Riveron 2016; Rodríguez-Yc 2013, 2018).

Ground stone studies are not often pursued for many reasons, including the sheer volume of artifacts, the size and weight of the tools that make curation and storage difficult, the wide range of raw materials, and the difficulty of sourcing some rock types. Additionally, ground stone studies rarely warrant the attention of M.A. or Ph.D. level research. By our calculations, only 10 theses have focused concertedly on GST in the Maya region in the last 20 years, six master’s-level investigations (de Chantal 2019; Delu 2007; Duffy 2011; Tibbits 2012; Turuk 2007; Ward 2013) and five Ph.D. theses (i.e., Abramiuk 2005; Duffy 2021; Jaime-Riveron 2016; Rodríguez-Yc 2013; Tibbits 2016). This scenario underscores just how little research attention has been focused on this prevalent artifact category by junior researchers, to say nothing of the scant attention from senior scholars. We hope that the studies described herein will help to invigorate renewed research interest on GST assemblages throughout the Eastern Maya Lowlands. Ground stone technology has remained “one of the last bastions of ‘common sense’ interpretation in archaeology” (Carter 2008:67) for too long. It is time that GST, and specifically granite GST, have their turn in the scientific spotlight.