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 

 reduced. No effervescence nor complete solution in nitric 

 acid, cold or heated. 



Dif. Distinguished from green malachite as stated undei 

 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 Wolcotville, 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. 



Dibptase 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=375. Gr=34. From Li- 

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

 to blue, and also dark blue, H=2 5— 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 m mummilated coat- 

 ings H=45 — 5. Gr=404. Contains 33 8 of arsenic acid and 594 

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

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

 an inch broad. H=2'5. Gr=28 — 29. Contains 14 per cent, of 

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

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

 H=3. Gr=42. Contains 367 per cent, of arsenic acid, to 5b - 4 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 giecn color. It 



How does chrysocolla differ from green malachite 1 Where is it 

 abundant in the U. States ? Whnt is its use ? 



