58 The American Naturalist. [.Januar* 



Cloizeaux 1 notes the similarity in habit between chalcopyrite crystals- 

 from Cuba and those of the French Creek Mines in Chester Co., 2 Pa. 

 A comparison of recent analyses of violan and anthochroite leads 

 Igelstrom 3 to the conclusion that the two are identical. — In a recent 

 brochure of the American Geological Society, Kunz 1 announces the 

 discovery of small diamonds in the alluvial sands of Plum Creek, 

 Pearce, Co., Wis., and the occurrence of fire opal in a vesicular basalt 

 at Whelan, Washington. — Sandberger 5 has found pseudomorphs of 

 markasite after pyrargyrite at Chanarcillo, Chile. 



Miscellaneous.— Syntheses.— Lorenz 6 has produced crystallized 

 zinc sulphide by the sublimation of the amorphous salt in an atmospheie 

 of ammonium chloride. The action is explained as taking place in two 

 stages— first, the formation of zinc chloride and its sublimation, and sec- 

 ondly , the action of sulphuretted hydrogen u pon this salt. By the action 

 of dry H a S on the respective metals cry stalized troilite, millerite,wurtzite 

 and greenockite were formed. The first is in little opaque tabular crys- 

 tals, that are at first silver white and afterwards bronzy-yellow in color* 

 According to Prof. Groth, they are probably hemimorphic. In addi- 

 tion to the greenockite there were produced in the same operation other 

 crystals that are seemingly cadmium sulphide.— Though the synthet- 

 ical production of augite is not a difficult problem, that of hornblende 

 has heretofore resisted the best efforts of mineralogists to effect it. 

 Chrustschoff 7 has however lately succeeded in obtaining the mineral by 

 heating in a glass tube, from which the air had been extracted, a mixture 

 of dialysed colloidal silicic acid containing Sfc of SiO., and dialysed 

 solutions of A1 2 3 , Fe (OH) s and Fe (OH) 2 , with lime water, freshly 

 prepared Mg (OH) 2 suspended in water, and a few drops of sodium and 

 potassium hydroxides. Upon heating these together for about three 

 months at 550° the mixture became of a dirty-brownish-green color, 

 when it was found to contain tiny hard grains of hornblende, analcite 

 quartz, feldspar and diopside. The hornblende crystals were bounded 

 by co P*T , PocT and oo P. Their extinction c A C=17°50'. Their 



JBull. Soc. Franc, d. Min., XIII, p. 335. 

 2 Cf. American Naturalist, 1889, p. 528. 

 3 Neues. Jahrb. f. Min., etc., 1890, II, p. 271. 



