156 DESCRIPTIONS OF MINERALS. 
Goslarite.—Sulphate of Zinc. White Vitriol. 
Trimetric. Cleavage perfect in one direction. JA J= 
90° 42’. 3 
Color white. Lustre vitreous. Easily soluble ; taste as- 
tringent, metallic, and nauseous. Brittle. H.=2-2%. G.= 
1°9-2°1. 
Composition. Z4nO,S+7 aq.=Zine oxide 28°2, sulphur 
trioxide 27°9, water 43°9=100. B.B. gives off fumes of 
zine on charcoal, which cover the coal. 
Obs. Results from the decomposition of blende. Occurs 
in the Hartz, in Hungary, in Sweden, and at Holywell in 
‘Wales. 
Sulphate of zinc is extensively employed in medicine and 
dyeing. or these purposes itis prepared to a large extent 
_ from blende by decomposition, though this affords, owing to 
its impurities, an impure sulphate. It is also obtained by 
direct combination of zinc with sulphuric acid. 
White Vitriol, as the term is used in the arts, is one form 
of sulphate of zine, made by melting the crystallized sul- 
phate, and agitating till it cools and presents an appearance 
like loaf sugar. 
Kéottigite. A hydrous zinc-cobalt arsenate of reddish color (owing 
to presence of cobalt) from Schneeberg 
Adamite. A lydrous zinc-arsenate of honey-yellow to violet color, 
from Chili. 
Smithsonite.—Carbonate of Zine. 
Rhombohedral. & A R=107° 40... Cleavage RF perfect. 
Massive or incrusting ; reniform and stalactitic. 
Color impure white, sometimes green or brown; streak 
uncolored. Lustre vitreous or pearly. Subtransparent to 
translucent. Brittle H.=5. G.=4:3-4-45. 
Composition. Zn O,C=Carbon dioxide 35:2, zinc oxide 
64:8 (four-fifths of which is pure zinc)=100. Often con- 
tains some cadmium. B.B. infusible alone, but carbonic 
acid and oxide of zinc are finally vaporized. Effervesces in 
nitric acid. Negatively electric by friction. 
Diff. The etfervescence with acids distinguishes this 
mineral from the following species; and the hardness, diffi- 
cult fusibility, and the zinc fumes before the blowpipe, from 
the carbonate of lead or other carbonates. Besides, the 
crystals over a drusy surface terminate usually in sharp 
turee-sided pyramids. 
