98 NATIVE SULPHUR. 



mercury is mostly obtained ; sulphuret of lead is galena, the 

 usual ore of lead. It is also sparingly met with in the con- 

 dition of sulphuric and sulphurous acids. 



NATIVE SULPHUR. 



Trimetric. In acute octahedrons, and secon- 

 daries to this form, with imperfect octahedral 

 cleavage. Also massive. 



Color and streak sulphur yellow, sometimes 

 orange yellow. Luster resinous. Transparent 

 to translucent. Brittle. H = l*5 — 2*5. Gr = 

 2-07. 



Native sulphur is either pure or contaminated with clay 

 or bitumen. It sometimes contains selenium, and has then 

 an orange yellow color. 



Dif. It is easily distinguished by burning with a blue 

 flame and a sulphur odor. 



Obs. The great repositories of sulphur are either beds 

 of gypsum and the associate rocks, or the regions of active 

 or extinct volcanoes. In the valley of Noto and Mazzaro in 

 Sicily, at Conil near Cadiz in Spain, Bex in Switzerland, 

 and Cracow in Poland, it occurs in the former situation. 

 Sicily and the neighboring volcanic islands, Vesuvius and 

 the Solfatara in its vicinity, Iceland, Teneriffe, Java, Hawaii, 

 New Zealand, Deception island, and most active volcanic 

 regions afford more or less sulphur. The native sulphur of 

 commerce is brought mostly from Sicily, where it occurs in 

 beds along the central part of the south coast and to some 

 distance inland. It is often associated with fine crystals of 

 sulphate of strontian. It undergoes rough purification by 

 fusion before exportation, which separates the earth and clay 

 with which it occurs. Sixteen or seventeen thousand tons 

 are annually imported from Sicily into England alone. 

 Sulphur is also exported from the crater of Vulcano, one of 

 the Lipari islands, and from the So'fatara near Naples. 



On the Potomac, 25 miles above Washington, fine speci- 

 mens of sulphur are found associated with calc spar in a gray 

 compact limestone. Sulphur is also found as a deposit about 

 springs where sulphureted hydrogen is evolved, and in cavi- 

 ties where iron pyrites have decomposed. Localities of the 



What is the crystallization of sulphur 1 Mention its other characters. 

 Where is the sulphur of the arts obtained' 



