COPPER.
321
of Cornwall , &c. The gangues of native copper are granite, gneiss, mica-slate, day-slate, quartz, carbonate or fluate of lime, sulphate of baryte?, &c. The most remarka-ble masses of native copper hitherto observed were—first, one in Brazil , 14 leagues fromBasa, which weighed 2616 pounds; and secondly, another which Dr. Francis-le-Barondiscovered in America to the south of Lake Superior . It was nearly 15 feet in circum-ference.
2. Sulphuret of Copper , Ike vitreous ore of Brochant. The texture of this ore is com-pact ; its fracture, conchoidal, surface sometimes dull; color, iron black or lead eray, oftenbluish, iridiscent, or reddish from a mixture of protoxyde. It is easily melted even bythe heat of a candle; but more difficult of reduction than protoxyde. This ore yields tothe knife, assuming a metallic lustre when cut. Its density varies from 4-8 to 5*34. Itsc ptnposition, according to Klaproth , is 78*5 copper, 18*5 sulphur, with a little iron andsilica. Its equivalent constitution by theory is 80 copper+ 20 sulphur = 100; whence<8*5 of metal should be associated with 19*6 of sulphur. This ore is therefore one ofthe richest ores, and forms very powerful veins, which likewise contain some orange pro-toxyde. It is to be found m all considerable copper districts j in Siberia, Saxony, Sweden ,a od especially Cornwall , where the finest crystals occur.
. 3. Copper Pyrites resembles in its metallic yellow hue, sulphuret of iron ; but the latterls Jess pale, harder, and strikes fire more easily with steel. It presents the most livelyra mbow colors. Its specific gravity is 4*3. It contains generally a good deql of iron,as the following analysis will show : copper 30, sulphur 37, iron 33, in 100 parts. Ac-cording to Hisinger , the Swedish pyrites contains 63 of copper, 12 of iron, and 25 of sul-Phur. These ores occur in primitive and transition districts in vast masses and powerful* e i ns I and are commonly accompanied with gray copper, sulphuret of iron, sparry iron,u Phurets lead, and zinc.
4 * Cray Copper has a steel gray color, more or less deep, either shining or dull; frac-uneven; a distinct metallic lustre; difficult of fusion at the blowpipe ; it communi-
ture
j a ui&imct lusiic ; uinu-un ui iumuii ai me uiuwjiipt:
s j t ; s glass of borax a yellowish-red color. Its density in crystals is 4-86. Its compo-ex , n ls very variable ; consisting essentially of copper, iron, antimony, and sulphur. Thet a i n ° rall °n of this ore is profitable, in consequence of the silver which it frequently con-conn' ^ occurs in primitive mountains; and is often accompanieU with red silver ore,g Pe !pWrites, and crystallized quartz.
Verv y r °t° x yd p - of Copper, or red oxyde of Copper : its color is a deep red, sometimes^ttcib/'^ly’ especially when bruised. It is friable, difficult of fusion at the blowpipe, rc-liqu; / on burning charcoal, soluble with effervescence in nitric acid, forming a greeng k tls constitution, when pure, is 88*9 copper-)- 11*1 oxygen = 100.and it iacC 'oxyde of Copper is of a velvet black, inclining sometimes to brown or blue;Con >posjt** Ulr * es tbe metaliic l ustre on being rubbed. It is infusible at the blowpipe. Its_ 7.
Its?bich
"utton is, copper 80 +oxygen 20) being a true peroxyde.
Hydrosilicate of Capper consists essentially of oxyde of copper, silica, and water,green ; and its fracture is conchoidal with a resinous lustre, like most minerals
but '°? la ‘ n water. Its specific gravity is 2*73. It is infusible at the blowpipe alone.. 8 £io ? easiIy with borax ‘
S ' sl * n g of aSC Copper, or Emerald Malachite; a beautiful but rare cupreous mineral, con-
9. Cart° X ^ e op C0 PP er j carbonate of lime, silica, and water in varying proportions,beautiful ° nate °f Copper, Malachite, is of a blue or green color. It occurs often in
10. s ‘ cr 5’st a ls.
The bl Ue Pj 1nle °f Copper, Blue Vitriol , similar to the artificial salt of the laboratorjC0 PPer i s - a ! ar which flows from certain copper mines is a solution of this salt. TheU. jq , 0 ai y Procured in the metallic state by plunging pieces of iron into it.
“lack. It a a * e °f Copper is of an emerald green, or verdigris color, with some spots ofd )ssolve s resents fibrous or tuberculous masses with a silky lustre in the fracture. ItP'Pe, and is r lt p 1C * aC1< ^ without effervescence, forming a Jilue liquid; melts at the blow-ts Powder ^ eallc Ible upon charcoal, with the aid of a little grease, into a metallic globule.12. Muriat^ P.°L C0 I° r flame green, like the powder of muriate of copper.a rkable hlu e | ”°PP er is green of various shades ; its powder imparts to flame a re-? Sl 'y reclu ce( i u r “ reen c °lor. It dissolves in nitric acid without effervescence ; and isS S. of oxvde j ,0re tl,e blowpipe. Its density is 3*5. By Klaproth ’s -analysis, it con-“PP^ 73, muriatic acid 10, water 17.
Witu’ f -‘*hali n , r f, ^ °Pper. It occurs in beautiful blue crystals. Before the blowpipe itb charcoal. 3 o mes ° P a » arlic odor, and it affords metallic globules when in contactfilin' 1 ar tiele Tyr more upon the ores at the end of this article.ti on es . ; ar >d shall co E 7' AI - 1 -' cr:BG I have described the mode of working certain coppeiof , h ’ mter estm» ■ 3nlent myself here with giving a brief account of two cupreous forma-*p, e C0 pper veino a r^r, 0 °^* ca ' P°int of new ; that of the copper slate of Mansfeldt, andFhe curious s ,c naof Co .mwall.
a 0 bituminous schist in the first of these localities, are among the21