PHYSIOGRAPHY. 277 



White Vitriol. 



WHITE VITRIOL. Prismatic Vitriol-Salt. 

 MOHS. 



In efflorescences and crusts. It crystallizes in right 

 rhombic prisms. M on M =90 42'. 



Lustre vitreous. Color white. Translucent. 



Brittle. Hardness = 2-0 ... 2-5. Sp. gr. = 2-036. 

 Taste astringent, nauseous and metallic. 



1. It is very easily soluble in water; before the blow-pipe it froths, 

 and covers the charcoal with a white coating. 

 i 2. Analysis. 



By KLAPROTH. 



Oxide of zinc 27-5 



Oxide of manganese 0-5 



Sulphuric acid 20-0 



Water 500 



3. It arises from the decomposition of Blende, and is found in small 

 quantity in the Rammelsherg near Goslar in the Hartz, at Schemnita in 

 Hungary, at Fahlun in Sweden, at Holy well in Flintshire. 



WILLEMITE. Axotomous Zinc-Baryte. 



Primary form. Rhomboid. P on P about, =133. 



Secondary form. Six-sided prism terminated by the fa- 

 ces of the primary rhomboid. 



Cleavage, indistinct, perpendicular to the axis of the 

 rhomboid, or parallel with the base of the six-sided prism. 



Lustre resinous. Color white, yellowish or red. Trans- 

 lucent or opake. 



Hardness =5'0 . . . 5-5. Sp. gr .=4-0 . . . 4-1. 



Compound Varieties. Reniform. Massive, impalpa- 

 ble. Color reddish brown. 



1. It consists of a silicate of zinc with a very little oxide of iron. 



2. It occurs with Calamine upon the Old mountain in Limburg. 



WITHAMITE. (See Epidote.) 

 VOL. ii. 24 



