and Laboratory Methods. 1513 



NOTES ON RECENT MINERALOGICAL 

 LITERATURE. 



Alfred J. Moses and Lea McI. Luquer. 



Books and reprints for review should be sent to Alfred J. Moses, Columbia University, 



New York. N. Y. 



Clarke, FW., and Steiger, George. Experi- ^he article treats of the fractional 

 ments Relative to the Constitution of Pecto- 



lite, Pyrophyllite, Calamine, and Analcite. analysis of silicates by means of various 

 Am. Jour. Sci. iv, 8: 245, 1899. reagents, in order to gain evidence 



bearing upon their chemical structure. 



Pcctolite proved to be a true metasilicate by ignition and solution in sodium 

 carbonate, the mineral being decomposed and losing practically \ of its SiOg, 

 as required by theory. 



PyropJiyllite not proved to be a metasilicate by same test. May be regarded 

 as having formula, SigOg^Al — OH, 



Calamijie tests as a rule yielded- negative results, but supported the usual 

 formula. 



Analcite appeared not to be a metasilicate, but may be a mixture of ortho- 

 and tri-silicate, represented by formula, Al4Na4(Si04)2(Si3 0g)2 • 4H2O. 



Analcite and leucite determined by authors to belong to garnet-sodalite 



group. L. IMcI. L. 



Prior, G. T. and Spencer, L. J. The Identity Binnite possesses the same degree of 

 of Binnite with Tennantite, and the Chemi- i /^ • i 



cal Composition of Fahlerz. Min. Mag. 12 : symmetry as the Cornish tennantite, 

 184, 1899. being simply better developed and hav- 



ing more and brighter faces. 

 Tetrahedrite (Fahlerz) appears to have the formula 3 CugS. (Sb.As)2S.j in 

 the case of the simple sulphantimonite or sulpharsenite of copper. The Fe and 

 Zn appear to be the disturbing elements, producing the 4 : 1 original formula of 

 Rose. 



As a result of many analyses the author proposes the new formula 3 R'gS • 

 R'"2S3+^[6R"S .R'"2S,3], in which R'=Cu, Ag ; R"=Fe Zn ; R"'==Sb, As, 

 Bi ; and .r=a small fraction, often ^ or \, but rising to \ in the case of the 

 highly ferriferous tetrahedrite " coppite." 



Many tests of the new formula are given by reference to to analyses. 



L. McI. L. 



Hartley, E. G. G. Communications from the Fharmacosiderite. — As a result of care- 

 Oxford Mineralogical Laboratory on the , , ... r^ • ^ ^ 

 Constitution of the Natural Arsenates and l^l analysis, m green Cornish crystals, 

 Phosphates. Min. Mag. 12: 152, 1899. the following formula was proposed: 



2 Fe ASO4 . Fe[0(H, K)]3 . 5 HgO. 



The undoubted presence of K (new to pharmacosiderite) is of interest. 



During the course of the investigation, the apparent permeability of the 

 mineral to certain liquids was shown. A green transparent crystal immersed in 

 ammonia turned red, and became green again in hydrochloric acid. 



L. McI. L. 



