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On pink epsomites and fauserite

Published online by Cambridge University Press:  14 March 2018

Max H. Hey
Max H. Hey*
Affiliation:
British Museum of Natural History
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Extract

In 1865 A. Breithaupt described a new mineral from Herrengrund, Hungary, to which he gave the name of fauserite. It formed very pale pink crystalline aggregates and prismatic crystals, with prism angle near 88°42′ (over a), apparently orthorhombic, and cleavage b(010). Two other prisms with angles (over a) 54°39′ and 107° 50′ were observed, and a pyramid p, giving mp= 52° ; these would correspond to forms (210), (340), and (111), and the angles are near those of epsomite. An analysis by Mollnár gave the figures shown under I below—a magnesium and manganese sulphate hexahydrate, with the molecular ratio MgSO4(Mn,Mg)SO4 = 31.62 %. There is no evidence that the analysed material (stated to be crystalline) was homogeneous.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 22 , Issue 133 , June 1931 , pp. 510 - 518
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1931

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References

page 510 note 1 A. Breithaupt, Berg- und Hüttenmännische Zeitung, 1865, vol. 24, p. 301.

page 510 note 2 The second analysis quoted by Dana is Mollárs theoretical figures.

page 510 note 3 J. Loezka, Math. Természett. Közlem. Budapest, 1891, vol. 24, p. 350; Math. Naturwiss. Ber. aus Ungarn, 1891, Vol. 8 (for 1889-1890), p. 108.

page 510 note 4 J. D. Dana, Syst. Min., 6th edit., 1892, p. 941.

page 514 note 1 The analyses were performed by Mr. S. E. Ellis of the Mineral Department, the method used being as follows: a portion of the solution or moist crystals was weighed out, diluted to 250 e.c., and an aliquot part taken for the estimation of sulphate as BaSO4. In a second portion (MnO+MgO) was estimated as the mixed pyrophosphates, while a third served for the manganese estimation. In the manganese-rich solutions and crystals this was carried out gravimetrically, the manganese being precipitated as sulphide and converted to pyrophosphate, but when more magnesium was present, the volumetric determination of manganese by Volhard's method, with KMnO4 and zinc acetate, was employed. Water was obtained by difference.

page 514 note 2 The composition of the eutectic mixture could be found if desired, but is of no value. If in fig. 1 l and l′ (derived from fig. 2) be the compositions of the two mixed crystals involved in the eutectic, the composition of the mixture must lie along ll′, and is given by the point at which the tie-line joining the compositions of solution and moist crystals cuts ll′.

page 515 note 1 The dotted tie-lines (e.g. LMC) in fig. 1 are drawn in by the aid of the smoothed curve of fig. 2, the actual tie-lines between the analyses of liquid and crystals being omitted for clarity.

page 516 note 1 The analysis is stated to have been made on clear crystals, which makes it improbable that the low water was due to efflorescence. On the other hand, the crystals might well have been a mixture, since it is unlikely that the best developed material would be used, and the author has observed that crystals of (Mg,Mn)SO4.7H2O and (Mn,Mg)SO4.5H2O are not readily distinguished unless well developed or unless optical examination is resorted to. There is a third but unlikely possibility; the analysed crystals may have really been a hexa- hydrate, since monoclinic and tetragonal series of hexahydrates are known among the vitriols. But Breithaupt's measurements cannot be reconciled with either series.

page 516 note 2 Epsomite is orthorhombic and has the b-cleavage, mm′″ = 89∼ 26′ (fauserite 88° 42′).

page 517 note 1 C. F. Rammelsberg, Ann. Phys. Chem. (Poggendorff), 1854, vol. 91, p. 342.

page 517 note 2 Hollmann, R., Zeits. Physik. Chem., 1901, vol. 37, p. 209 Google Scholar (footnote 4).

page 518 note 1 R. Balló [Magyar Chem. Folyóirat, 1907, vol. 13, pp. 17, 33, 49, 65, 81, and 97]; abstr, in Zeits. Kryst. Min., 1910, vol. 47, p. 298.

page 518 note 2 Collins, H. F., Min. Mag., 1923, vol. 20, p. 32.CrossRefGoogle Scholar