674 SCIENTIFIC RECORD FOR 1883. 



little magnesia, lime, and iron protoxide. The results obtained are not 

 very satisfactory because the material analyzed contained about six- 

 teen per cent, of gangue. The composition brings empholite near the 

 davreuxite of M. de Koninck, which, however, differs in containing less 

 water. The gangue in which the crystals of empholite are imbedded 

 consists essentially of damourite and pyrophyllite ; it forms a white 

 finely micaceous mass with greasy feel; some other associated minerals 

 are rutile, menaccanite, svanbergite, black tourmaline. (Bull. Soo. Min., 

 VI, 40.) 



Groddeclcite. — Described by Arzruni (Zeitsch. Kryst., viii, 343), as 

 a new zeolite belonging to the chabazite group, more properly to be 

 regarded as a variety of gmelinite. It occurs in small transparent crys- 

 tals similar to ordinary gmelinite in habit and angles. In composition 

 it corresponds with gmelinite in general, but contains nearly 8 per cent, 

 of iron sesquioxide and 3 per cent, of magnesia. The mineral is known 

 from a single specimen only, which was obtained in 18G7 from Andreas- 

 berg iu the Harz. 



Igelstromite. — This is properly a variety of the mineral knebelite. It 

 is described by Mats Weibull as occurring with other manganese min- 

 erals at Vester-Silfberg, Norrbarke parish, Sweden. It forms grayish- 

 black crystalline masses with irregular texture, sometimes almost homo- 

 geneous and again mixed with magnetite and carbonate of calcium and 

 manganese. The crystalline form was not determined, but two cleav- 

 ages were observed making an angle of 131° with each other, and also 

 a third indistinct cleavage at right angles to the others. It is trans- 

 lucent with a yellowish color and vitreous to greasy luster. The specific 

 gravity is 4.17. An analysis showed that it was a silicate containing 47 

 per cent, of iron protoxide, and 19 per cent, of manganese protoxide, 

 with 3 per cent, of magnesia. This makes it a member of the chrysolite 

 group intermediate between the iron chrysolite called fayalite, and the 

 iron-manganese chrysolite called knebelite. It should be added that 

 Heddle has earlier used this name as a synonym of pyroaurite. (Geol. 

 For. Fork., Stockholm, vi, 500.) 



Jeremejeffite. — A remarkable mineral both from its physical and chem- 

 ical characters. It was brought by the Russian engineer, M. Jeremejew, 

 from the Soktoui, southeast of Adun-Tschilon, in Western Siberia. It 

 was first examined chemically by M. Damonr (Bull. Soc. Min., vi, 20), 

 who gave it its new name. He described it as occurring in hexagonal 

 prisms resembling apatite and beryl in habit. Its hardness is 6.5, and 

 its specific gravity 3.28. It is transparent and almost colorless, with 

 vitreous luster on the fracture space. In composition Damour showed 

 it to be essentially a borate of aluminum containing also a little iron 

 protoxide. The crystalline form of the mineral has been exhaustively 

 studied by Websky (Jahrb.f. Min., 1884, 1, p. 1). He shows that while 

 in form the crystals are hexagonal, in fact only the outer shell is opti- 

 cally uniaxial, while the interior portion is made up of six segments all 



