133 



COPPER. 



COPPER. 



134 



It fuses before the blow-pipe to a globule, which is magnetic, owing to 

 the iron present. Gives sulphur-fumes on charcoal ; with borax 

 affords pure copper. The usual effect with nitric acid. 



This ore resembles native gold and also iron pyrites. It is dis- 

 tinguished from gold by crumbling when it is attempted to cut it, 

 instead of separating in slices ; and from iron pyrites in its deeper 

 yellow colour, and in yielding easily to the point of a knife, instead 

 of striking fire with a steel. 



Copper pyrites occurs in veins in granite and allied rocks; also in 

 grauwacke, Ac. It is usually associated with iron pyrites, and often 

 with galena, blende, and carbonates of copper. The copper of Fahlun, 

 Sweden, is obtained mostly from this ore, where it occurs with serpen- 

 tine in gneiss. Other mines of this ore are in the Harz, near Goslar, 

 in the Bannat, Hungary, Thuringia, &c. The Cornwall ore is mostly 

 of this kind, and 10,000 to 12,000 tons of pure copper are smelted 

 annually. There is much of this ore found in the United States. 

 Besides being mined for copper, this ore is used extensively in the 

 manufacture of blue vitriol (sulphate of copper) in the same manner 

 that sulphate of iron (copperas) is obtained from iron pyrites. 



Variegated Copper Pyrites. Monometric. Cleavage octahedral, 

 in traces. Occurs in cubes and octahedrons ; also massive. Colour 

 between copper-red and pinchbeck-brown ; tarnishes rapidly on expo- 

 sure ; streak pale grayish-black, and but slightly shining. Brittle. 

 Hardness, 3. Specific Gravity, 5. Composition : 



Sulphur 25'7 



Copper 62-8 



Iron 11-6 



It fuses before the blow-pipe to a globule, attractable by the magnet. 

 Ou charcoal affords fumes of sulphur. Mostly dissolved in nitric acid. 

 This ore is distinguished from the preceding by its pale reddish-yellow 

 colour. It occurs with other copper ores in granitic and allied rocks, 

 and also in secondary formations. The mines of Cornwall have 

 afforded crystallised specimens, and it is there called from ita colour 

 Horseflesh Ore. Other localities of massive varieties are Ross 

 Island, Killarney, Norway, Hesse, Silesia, Siberia, and the Baunat. 

 Fine crystallisations occur in some of the United States. 



Gray Copper Ore. Monometric. Occur* in modified tetrahedrons, 

 and also in compound crystal*. Cleavage octahedral, in traces. 

 Colour between steel-gray and iron-black ; streak nearly as the 

 colour. Rather brittle. Hardness, 3 to 4. Specific Gravity, 

 4*75 to 5.1. Composition : 



Sulphur 26-3 



Copper 38 - 6 



Antimony TI'5 



Arsenic 7"2 



together with some iron, zinc, and silver, amounting to 15 per cent. 

 It sometimes contains 30 per cent, of silver, in place of part of the 

 copper, and is then called Argentiferous Gray Copper Ore, or Silver 

 Pahlerz. The amount of arsenic varies from to 10 per cent. One 

 variety from Spain included 10 per cent, of platinum, and another 

 from Hohenstein some gold ; another from Tuscany 2'7 per cent, of 

 mercury. These varieties give off before the blow-pipe fumes of 

 arsenic and antimony, and after roasting yield a globule of copper. 

 It dissolves, when pulverised, in nitric acid, affording a brownish-green 

 solution. Its copper-reactions before the blow-pipe, and in solution 

 in nitric acid, distinguish it from the gray silver ores. The Cornish 

 mines, Andreasberg in the Harz, Kremnitz in Hungary, Freiberg in 

 Saxony, Kapnik in Transylvania, and Dillenberg in Nassau, afford 

 fine crystallisations of this ore. It is a common ore in the Chilian 

 mines, and is worked there and elsewhere for copper, and often also 

 for silver. 



Red Copper Ore. Monometric. In regular octahedrons, and modi- 

 fied forms of the same. Cleavage octahedral. Also massive, and 

 sometimes earthy. Colour deep red, of various shades ; streak 

 brownish-red. Lustre adamantine, or sub-metallic ; also earthy, 

 sub-transparent to nearly opaque. Brittle. Hardness, 3'5 to 4. 

 Specific Gravity, 6. Composition : 



Copper 88'88 



Oxygen 12 



Before the blow-pipe on charcoal it yields a globule of copper. 

 It dissolves in nitric acid. The earthy varieties have been called Tile 

 Ore,,(rom the colour. From cinnabar it differs in not being volatile 

 before the blow-pipe, and from red iron ore in yielding a bead of 

 copper on charcoal, and copper-reactions. It occurs with other 

 copper ores in the Bannat, Thuringia, Cornwall, at Chessy, near Lyon ; 

 in Siberia, ami Brazil ; also in the United States. The octahedrons 

 are often green, forming a coating of malachite. 



Black Copper. Tenorite. An oxide of copper occurring as a black 

 powder and in dull black masses and botryoidal concretions, in veins 

 or along with other copper ores. From Cornwall, and also the Vesn- 

 i lavas. It is an abundant ore in some of the copper mines of the 

 ippi Valley, and yields 60 to 70 per cent, of copper. The 

 of copper are easily smelted by heating with the aid of 

 charcoal alone. They may be converted directly into sulphate 

 or blue vitriol by means of sulphuric acid, but are more 

 valuable for the copper they afford. 



Blue Vitriol. Sulphate of Copper. Copperas. Triclinate. In oblique 

 rhomboidal prisms ; also as an efflorescence or incrustation. Colour 

 deep sky-blue ; streak uncoloured. Sub-transparent to translucent. 

 Lustre vitreous. Soluble. Taste nauseous and metallic. Hardness, 

 2 to 2-5. Specific Gravity, 2'21. Composition : 



Sulphuric Acid 

 Oxide of Copper 

 Water 



31-7 

 32-1 



36.2 



A polished plate of iron in a solution becomes covered with copper. 

 It occurs with the sulphurets of copper as a result of their decompo- 

 sition, and is often in solution in the waters flowing from copper 

 mines. Occurs in the Harz, at Fahlun in Sweden, and in many 

 other copper regions. 



Blue Vitriol is much used in dyeing operations, and in the printing 

 of cotton and linen ; also for various other purposes in the arts. It 

 has been employed to prevent dry rot by steeping wood in its solu- 

 tion, and is a powerful preservative of animal substances ; when 

 imbued with it and dried they remain unaltered. It is afforded by 

 the decomposition of copper pyrites, in the same manner as green 

 vitriol from iron pyrites. It is manufactured for the arts from old 

 copper sheathing, copper turnings, and copper refinery scales. The 

 scales are readily dissolved in dilute sulphuric acid at the temperature 

 of ebullition ; the solution obtained is evaporated to the point where 

 crystallisation will take place on cooling. Metallic copper is exposed 

 in hot rooms to the atmosphere after it has been wetted in weak 

 sulphuric acid. By alternate wetting and exposure it is rapidly 

 corroded, and affords a solution which is evaporated for crystals. 

 400,000 Ibs. is the annual consumption of blue vitriol in the United 

 States. In some mines the solution of sulphate of copper is so 

 abundant as to afford considerable copper, which is obtained by im- 

 mersing clean iron in it. It is called Copper of Cementation. At the 

 copper springs of Wicklow, Ireland, about 500 tons of iron were laid 

 at one tune in the pits : in about twelve months the bars were 

 dissolved, and every ton of iron yielded a ton and a half, and some- 

 times nearly two tons, of a precipitated reddish mud, each ton of 

 which produced 16cwt. of pure copper. The Rio Tinto mine, in 

 Spain, is another instance of working the sulphate in solution. These 

 waters yield annually ISOOcwt. of copper, and consume 2400 cwt. of 

 iron. 



Green Malachite. Green Carbonate of Copper. Monoclinate. Usual in 

 incrustations, with a smooth tuberose botryoidal or stalactitic surface. 

 Structure finely and firmly fibrous ; also earthy. Colour light green ; 

 streak paler. Usually nearly opaque. Crystals translucent. Lustre 

 of crystals adamantine, inclining to vitreous ; but fibrous incrustations 

 silky, on a cross fracture. Earthy varieties dulL Hardness, 3'5 to 4. 

 Specific Gravity, 4. Composition : 



Carbonic Acid 18 



Oxide of Copper . . . . . . 70'5 



Water 11-5 



Dissolves with effervescence in nitric acid. Decrepitates and blackens 

 before the blow-pipe, and becomes partly a black scoria. With borax 

 it fuses to a deep green globule, and ultimately affords a bead of 

 copper. It is readily distinguished by its copper-green colour and its 

 association with copper ores. It resembles a siliceous ore of copper, 

 CltryiocoUa, a common ore in the mines of the Mississippi valley ; 

 but it is distinguished by its complete solution and effervescence in 

 nitric acid. The colour also is not the bluish-green of chrysocolla. 

 Green malachite usually accompanies other ores of copper, and forms 

 incrustations, which when thick have the colours blended, and 

 extremely delicate in their shades and blending. Perfect crystals 

 are quite rare. The mines of Siberia, at Nischne Tagilsk have 

 afforded great quantities of this ore. A mass partly disclosed mea- 

 sured at top 9 feet by 18 feet; and the portion uncovered contained at 

 least half a million pounds of pure malachite. Other noted localities 

 are Chessy in France, Sandlodge in Shetland, Schwartz in the Tyrol, 

 Cornwall, Australia, and the island of Cuba. This mineral receives 

 a high polish, and is used for inlaid work, and also ear-rings, snuff- 

 boxes, and various ornamental articles. It is not much prized in 

 jewellery. Very large masses are occasionally obtained in Russia, 

 which are worked into slabs for tables, mantel-pieces, and vases, 

 which are of exquisite beauty, owing to the delicate shadings and 

 radiations of colour. In the Great Exhibition of 1851 there were 

 magnificent specimens of this material in the shape of doors and 

 vases sent thither by the Emperor of Russia. At Versailles there is 

 a room furnished entirely with tables, chairs, &c., wrought in 

 malachite, and the same are to be found in other European palaces. 

 At Niscbne Tagilsk, a block of malachite was obtained weighing 

 40 tons. Malachite is sometimes passed off in jewellery as turquoise, 

 though easily distinguished by its shade of colour and much inferior 

 hardness. It is a valuable ore when abundant, but it is seldom 

 smelted alone, because the metal is liable to escape with the liberated 

 volatile ingredient, carbonic acid. 



Aewtie. Slue Carbonate of Copper. Monoclinate. In modified 

 oblique rhombic prisms, the crystals rather short and stout ; lateral 

 cleavage perfect ; also massive ; often earthy. Colour deep blue, 

 azure, or Berlin blue ; transparent to nearly opaque ; streak bluish. 



