42 G. E. Moore—Amorphous Mercurie Sulphide. 
To facilitate comparison, I have arranged the properties of 
the native red and black and the artificial black mercuric sul- | 
phide in the following table :— 3 
ed (native). | Black (native). | Black (artificial), 
Always crystallized or crys- Always amorphous. 
Hin: 
Cleavage, perfect. Totally destitute of cleav-| sure high polish and 
age. | metallic lustre. Obtain- 
Lustre, adamantine, incli-|Lustre, metillic. ; ed by sublimation as 4 — 
ning to metallic in the black amorphous mass, 
darker varietie wit etalli lustre. 
(Fuchs, loc. cit.) 
Color, cochineal red, incli- Color, grayish black. 
ning to brownish and 
lead gray. 
Streak, scarlet. Streak, black. 
Specific gravity, 8-0—8-2. |Specific gravity, 7-701. ‘Specific gravity, 7-552. 
The difference between the two minerals seems to me 
greater than that between two varieties of the same species. I 
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