408 DESCRIPTIVE MINERALOGY. 



This mineral resembles some darlt varieties of pyroxene, from which it was first distin- 

 guished by Mr. Levy. Mr. Children found it to contain silica, iron, manganese, lime, and a 

 minute quantity of titanium. 



LOCALITY. 



St. Lawrence County. The only known locality of babingtonite in the United States, is 

 at Gouverneur in this county, where it was first noticed by Prof. Shepard, coating crystals of 

 feldspar. 



. _ ORDER III. ZINC. 



This order contains only a single species, viz : 



1 . Zinc Blende ; and to this may be added the artificial oxide known by the name of 

 Cadmia. 



ZINC BLENDE. 



[From the German, sigmfy'mg glisteiu?ig ; in allusion to its lustre.] 



Zinc Sulfure. Ho.iiij. — Sulpliuret of Zinc. Clcavcland and Phillips. — BlenJe, or Sulphurct of Zinc. TJwm- 

 so». — Dodecahedral Zinc-Blende. Jameson. — Dodecacdrisclie Granat-Blende. Mohs. — Blende. Bcudant 

 and Shtpard. 



Fig. 483. Description. Colour brown, yellow, grey, green, red and black. 



Streak varying with the colour. It occurs regularly crystallized ; also 

 massive and disseminated. Primary form the rhombic dodecahedron, 

 Fig. 483. Its secondary forms are very numerous. Cleavage perfect, 

 parallel with the primary faces. Fracture conchoidal. Brittle. Lus- 

 tre splendent, sometimes adamantine. Varies from transparent to 

 opaque. Hardness from 3.5 to 4.0. Specific gravity from 4.00 to 

 4.20. Before the blowpipe, it usually decrepitates ; and though gene- 

 rally infusible even with borax, it sometimes melts into a scoria 



( Thomso7i). Its powder in sulphuric acid gives out sulphuretted hydrogen. Difficultly soluble 



in nitric acid ; its solution giving a white precipitate with ammonia, which is soluble in an 



excess of the alkali. 



Zinc blende may be distinguished from those varieties of galena, garnet and oxide of tin, 



which it sometiiues resembles, by the ease with which it yields to cleavage in the direction of 



tlie primary faces. 



