COPPER ORES. 301 



The mineral varies much in the proportion of its constitu- 

 ents, as it is not crystallized. It blackens in the inner flame 

 of the blowpipe without melting. With borax it is partly 

 [■educed. No effervescence nor complete solution in nitric 

 acid, cold or heated. 



Dif. Distinguished from green malachite as stated under 

 that species. 



Obs. Accompanies other copper ores in Cornwall, Hun- 

 gary, the Tyrol, Siberia, Thuringia, &c. In Chili it ia 

 abundant at the various mines. In Wisconsin and Missouri 

 it is so abundant as to be worked for copper. It was for- 

 merly taken for green malachite. It also occurs at the Som- 

 erville and Schuyler's mine, N. J., at Morgantown, Penn., 

 and Wolbotville, Conn. 



Uses. This ore in the pure state affords 30 per cent, of 

 copper; but as it occurs in the rock will hardly yield one- 

 third this amount. Still when abundant, as it appears to be 

 in the Mississippi valley, it is a valuable ore. It is easy of 

 reduction by means of limestone as a flux. 



Dioptase is another silicate of copper, occurring in rhombohedral 

 crystals and hexagonal prisms. R : R=126° 24'. Color emerald- 

 green. Luster vitreous. Streak greenish. Transparent to nearly 

 opaque. H*=5. Gr=328. From the Kirghese Steppes of Siberia. 



Besides the above salts of copper, there are the following species, 

 which are of little use in the arts. 



Arsenates of Copper. — Euchroite has a bright emerald-green color, 

 and contains 33 per cent, of arsenic acid, and 48 of oxyd of copper. 

 Occurs in modified rhombic prisms. H=3 - 75. Gr=3'4. From Li- 

 bethen, in Hungary. Aphanesite is of a dark verdigris- green inclining 

 to blue, and also dark blue, H=25 — 3. Gr=419. It contains 30 

 per cent, of arsenic acid and 54 of oxyd of copper. From Cornwall. 

 Erinite has an emerald-green color, and occurs in mammilated coat- 

 ings H=4-5 — 5. Gr=404. Contains 338 of arsenic acid and 594 

 of oxyd of copper. From Limerick, Ireland. Liroconite varies from 

 dky-blue to virdigris-green, It occurs in rhombic prisms, sometimes 

 an inch broad. H=s2*5. Gr~2*8 — 29. Contains 14 per cent, of 

 arsenic acid, 49 of oxyd of copper. Olivenite presents olive-green to 

 brownish colors, and occurs in prismatic crystals or velvety coatings. 

 H=3. Gr=4 - 2. Contains 367 per cent, of arsenic acid, to 564 of 

 oxyd of copper. Copper Mica is remarkable for its thin foliated, or 

 mica-like structure. The color is emerald or grass-green. H=2. 

 Gr=255. It contains 21 per cent, of arsenic acid, 58 of oxyd of cop- 

 per, and 21 of water. From Cornwall and Hungary. Copper Froth 

 is another arsenate of a pale apple-green and verdigris green color. I 



How does chrysocolla differ from green malachite ? Where is it 

 abundant in the U. States 1 What is its use 1 



