422 



DESCRIPTIVE MINERALOGY. 



VITREOUS COPPER. 



Cuivrc Sulfur^. Ilatiy. — Sulphuret of Copper. Ckaveland and Phillips. — Disulphuret of Copper. Thnnson,. — 

 Vitreous Copper. Shepard. — Prismatic Copper Glance. Jameson. — Prismatischer Kupfer-Glanz. Mohi. — 

 Cbalkosine. Bcudant. 



Description. Colour blackish lead-grey. Streak similar. It oc- 

 curs regularly crystallized ; also in granular concretions and massive. 

 Primary form a right rhombic prism. Fig. 504. M on M' 119° 35'. 

 It is often found in regular six-sided prisms. (According to some au- 

 thors, the primary is a cube.) Cleavage very imperfect. Fracture 

 conchoidal and uneven. Lustre metallic. Opaque. Sectile. Hard- 

 ness from 2.5 to 3.0. Specific gravity from 5 . 69 to 5 . 80. Before 

 the blowpipe alone, fusible with sputtering ; and with carbonate of 



soda, gives grains of copper. Soluble in hot nitric acid, leaving the sulphur unacted on. 



When the solution is treated with excess of ammonia, it becomes of a fine blue colour. The 



copper is also deposited upon a clean plate of iron. 



Composition. Specimen from Siberia — Copper 78.50, sulphur 18.50, iron 2.25 (X^Za- 

 proth). 



Specimen from Cornwall — Copper 77.16, sulphur 22.16, iron 1.45 (Thomson). For- 

 mula CujS. 



Geological Situation. This mineral occurs in veins and beds, accompanying other ores 

 of copper. 



' localities. 



Columbia County. Vitreous copper, associated with copper pyrites, has been found in the 

 veins of galena which occur in the town of Canaan. It has also been observed on the farm 

 of John F. Catlin, of Austerlitz, in a vein of white quartz, passing through limestone ; also 

 on the mountain east of Green river. It is only found massive. 



Dutchess County. On the farm of Judge Bockee, in the town of Northeast, this mineral 

 has been found with similar associates to those just noticed. 



Mr. Mather informs us that small quantities of the black sulphuret of copper, galena, blende, 

 and the green and blue carbonates of copper, are extensively diffused in a stratum of calca- 

 reous conglomerate or breccia, in various parts of Greene, Ulster, Sullivan and Delaware 

 counties, but the stratum is nowhere more than eighteen inches in thickness. These mine- 

 rals, although frequently observed, do not, however, appear to exist in quantities sufficient to 

 give them any importance in an economical point of view.* 



Vitreous copper is found at the copper mines in New-Jersey and Connecticut. 



•Mather. Neu>-York Geological Reports, 1840. 



