426 



DESCRIPTIVE MINERALOGY. 



LOCALITIES. 



Green malachite has heretofore been found in this State only as an incrustation. Thus it 

 occurs on copper pyrites in the counties of Columbia, Dutchess and Sullivan, in the veins of 

 galena. In the same form, it has also been observed in the limestone of Erie county ; in the 

 grey band at Lewiston in Niagara ; in the trap in Rockland, and on magnetic iron ore at the 

 Phillips mine in Putnam. 



This mineral, in small quantities, having the fibrous character, and associated with the red 

 oxide and sulphuret of copper, occurs at the copper mines of Nev^-Jersey, and at the Per- 

 kiomen lead mine in Pennsylvania. The United States, however, has not hitherto afforded 

 very fine specimens. 



AZURITE. 



[In allusion to its colour.] 



Cuivre Carbonate Bleu. Hauy. — Blue Carbonate of Copper. ClcavcUnd and Phillips. — Blue Malachite. 

 Shepard. — Prismatic Blue Malachite. — Jameson. — Hemiprismatischer Lazur-Malacliit. Mohs. — Hydro- 

 carbonate of Copper. Tlumison. — Azurite. Bcudant. 



Description. Colour azure or berlin-blue, sometimes passing 

 into blackish blue. Streak similar but lighter. It occurs regularly 

 crystallized in concretions which are scopiform and stellular, radiated, 

 and also curved lamellar ; massive, globular, stalactitic and cellular. 

 Primary form an oblique rhombic prism. Fig. 509. M on M' 98° 

 50'; P on M or M' 91° 30' {Phillips). Cleavage perfect, parallel to 

 M and M' ; difficult parallel to P. Fracture conchoidal. Lustre 

 vitreous or vitreo-resinous. Transparent to translucent on the edges. 

 Brittle. Hardness from 3.5 to 4.0. Specific gravity from 3.50 to 

 3 . 80. Before the blowpipe, it blackens, decrepitates, and at length 

 fuses. Colours borax green. Dissolves in nitric acid with effervescence. The solution pro- 

 duces a blue colour with ammonia, and forms a coating of copper on a clean plate of iron. 



Composition. Copper 56.00, o.xygen 12.50, carbonic acid 25 . 00, water 6 . 50 ( Faw^we- 

 Un). Formula 3Cu0.2CO, 4- Aq. 



Geological Situation. It occurs in beds and veins in rocks of various ages, usually 

 associated with other ores of copper, galena, zinc blende, etc. 



localities. 

 Incrustations of azurite are found with copper pyrites at Sing-Sing in Westchester county ; 

 and the same mineral is also occasionally observed, forming thin scales on the limestone in 

 the same vicinity 



