254 NATIVE SULPHATE OF COPPER. 



Soluble in nitric acid, and redeposited by 

 copper. 



Localities.—' English. Cornwall : at Mount 

 Mine, Dolcoath, and North DoIcoath,Fowey 

 Consols, West Huel Darlington, Wills- 

 worthy Mine, with Arsenical Cobalt and 

 Copper Pyrites; Huel Golden, in thick con- 

 torted threads ; Huel Tremayne ; Huel Bro- 

 thers and other mines near Callina;ton. — 

 Irish. Ballycorus Mines, co. Dublin. — 

 Foreign. In splendid crj'stals and large 

 masses at the mines of Kongsberg, in Nor- 

 way. Saxony, chiefly at Freiberg, Schnee- 

 berg, and Johanngeorgenstadt. Bohemia, 

 principally at Przibram, Joachimsthal, and 

 Ratiborzitz. Schemnitz, in Hungary. Tran- 

 sylvania. Silesia. Deux Fonts. Andreas- 

 ■ berg, in the Harz. Alsace. Dauphine. 

 Kolywan and Nertschinsk, in Siberia. Java. 

 Mexico. Peru. Chili. North America. 



Brit Mus., Case 2. 



31. P. G. Principal Floor, Wall-cases 14 

 (British) ; 22 (Foreign). 



Native Silver generally occurs in veins 

 of Calcareous Spar or Quartz, traversing 

 gneiss, slate, and others of the older rocks. 



It is distinguished from Antimonial Silver 

 and Native Antimony by its hackly frac- 

 ture and malleability, the latter having a 

 foliated fracture and being brittle. 



The metal silver is the whitest of all the 

 metals. It is harder than gold, but softer 

 than copper, is elastic, gives a clear ringing 

 sound, is very malleable and ductile, may 

 be hammered info leaves 0000 1 of an inch 

 in thickness, and one grain of silver may be 

 drawn out into a wire 400 feet long. It 

 admits of being welded. 



Silver is used for a variety of useful and 

 ornamental purposes. Its hardness renders 

 it a useful medium of exchange, when 

 coined into money. Its brilliancy and white- 

 ness cause it to excel all other materials for 

 plate and similar articles of luxury ; and, in 

 consequence of its sonorous properties, it is 

 made into trumpets and other musical in- 

 struments. There is a great consumption 

 of silver, at the present day, in the process 

 of electrotyping. Certain preparations of 

 silver are also used in medicine. 



Native Sulphate of Copper and Iron, 

 M. F. Pisani. See Vitrioltte. 



Native Sulphur. Rhombic. Occurs in 

 regular crystals, the prevailing form of 

 which is an acute octahedron, composed of two 

 four-sided pyramids, with rhombic bases, and 

 sides composed of equal and similar scalene 

 triangular planes. It most commonly occurs 

 in amorphous compact masses, or in small 



NATIVE SULPHUR, 

 fragments or grains disseminated in other 

 minerals; sometimes pulverulent, in the 

 state of a loose or slightly coherent dull 

 powder, in the interior of other minerals, or 

 coating their surface, especially that of lava. 



Fig. 304. 



Fig. 305. 



Fig. 306. 



Colour sulphur-3'ellow, sometimes red, grey, 

 or brown, owing to the presence of im- 

 purities. Generally translucent, or very 

 nearly transparent at the edges, sometimes 

 opaque. Lustre usually more or less shin- 

 ing, and between resinous and adamantine. 

 Streak sulphur-yellow, sometimes reddish 

 or greenish. S'ectile. Verv brittle, and 

 sometimes friable. Fracture 'conchoidal, or 

 slightly splintery. Exhales a faint odour 

 when rubbed, and has a scarcely percep- 

 tible taste. Does not conduct electricity, but 

 becomes electrical when rubbed with other 

 bodies. H. 1-.5 to 2-5. S.G. 2-033 to 2-072. 



Co}np. S, or pure sulphur, often contami- 

 nated with other substances. 



Burns readily with a blue lantbent flame, 

 giving off strong odours of sulphurous acid, 

 and fusing to a brown liquid. 



Insoluble in water. Not acted on by 

 acids. 



Sulphur is found in most places where 

 salt mines or salt springs exist, and is very 

 common in volcanic countries, where it is 

 met with in the cavities and fissures of lava, 

 into which it litis been sublimed. It is found 

 in a state of powder, or in crusts, or irregu- 

 lar masses, or in crystals, concretions, sta- 

 lactites, &c. 



Localities — English. Cornwall, at Poldice 

 and Nangiles Mines, in cavities in Iron 

 Pyrites. Bole Hill, Derbyshire; and Dufton, 

 Westmoreland, on Galena. Alston, Cum- 

 berland, with Gypsum. — Irish. Brooklodge, 

 CO. Galway, with Calc Spar. Castle Cara, 

 CO. Mayo, in limestone. — Foreign. The 

 valleys of Noto and Mazzaro, in Sicily, in 

 horizontal beds,from two feettomore than 30 

 feet thick, near large masses of Gypsum, and 

 generally alternating with beds of limestone, 

 marl, and claj', and accompanied by Sulphate 

 of Strontian. The Sulphur is very irregularly 

 distributed, partly in large holes in corroded 

 limestone, where it generally forms small 



