COPPER. 425 



Ulster County. This mineral is occasionally found associated with galena, zinc blende, 

 etc. in quartz, at the Ellenville and Red-bridge mines. 



Westchester County. Copper pyrites has been found in the white limestone in various 

 parts of this county, but the localities are of little importance. Good specimens were for- 

 merly obtained in the immediate vicinity of the prison at Sing-Sing, where it is said that a 

 shaft was sunk, previously to the American Revolution, by a British officer. Native silver, 

 copper and lead ore, were the reputed products of the mine ; but the information which we 

 possess on the subject is quite vague. This mine was drained a few years since, but not 

 worked. The rock is the dolomitic limestone, containing pyroxene and some magnetic 

 pyrites. 



Rockland County. This mineral is sometimes sparingly disseminated in the trap at Pier- 

 mont. 



Warren County. Imperfect crystals have been found in white limestone in the town of 

 Chester. 



GREEN MALACHITE. 



[From the Greek fAaXajj^ri, a mallow ; because of its colour.] 



Cuivre Carbonate Vcrte. Hany. — Green Carbonate of Copper. Cleaveland and PMUips. — Green Malachite. 

 Shepard. — Hydrous Dicarbonate of Copper. Tkomson. — Hemiprismatic Green Malachite. Jameson. — 

 Hemiprismatischer Habronem Malachit. Moh$. — Malachite. Beudant. 



Description. Colour various shades of green. Streak green, but paler. It occurs regu- 

 larly crystallized, compact and earthy ; also in slender fibres, which are fasciculated or stel- 

 lated. Primary form an oblique rhombic prism. M on M' 107° 20' ; P on M or M' 112° 

 52' {Brooke). According to Phillips, the primary is a right oblique angled prism, M on M' 

 123° 35' ; and Beudant makes it a right rhombic prism, with the angles 103° and 77°. The 

 crystals are very minute, and usually compound. Cleavage perfect parallel to the planes P 

 and M ; difficult parallel to P {Phillips). Fracture uneven, conchoidal and even. Lustre 

 adamantine, inclining to vitreous, sometimes silky. Varies from translucent to opaque. 

 Brittle. Hardness from 3 . 5 to 4 . 0. Specific gravity from 3 . 50 to 4 . 00. Before the blow- 

 pipe, it becomes black after decrepitation, and is partly converted into a black scoria ; with 

 borax, it yields a bead of copper, and colours the flux green. From its solution, metallic 

 copper is precipitated by a clean plate of iron. 



Composition. Copper 56.00, oxygen 14.00, carbonic acid 21.25, water 8.75 {Vauque- 

 lin). Formula 2CuO.C02+Aq. 



Geological Situation. This mineral occurs associated with copper pyrites and other ores 

 of copper, in veins which traverse primitive, transition and secondary rocks. 



Min. — Part II. 54 



