200 DESCRIPTIONS OF MINERALS. 
Variscite (Peganite, Callainite) is another hydrous aluminum phos- 
pate ; it is of a light green color, of various shades, to deep emerald- 
green. From Montgomery County, Arkansas, and from Colorado ; also 
from Messbach, in Saxon Voigtland. F ischerite is a related mineral. 
Turquois. 
In opaque reniform masses without cleavage; of a bluish- 
green color, and somewhat waxy lustre. H=6 Ge 
—2°8. 
— Composition. Phosphorus pentoxide 82°6, alumina 46°9, 
water 20°3=100. B.bL. infusible, but becomes brown and 
colors the flame green ; soluble in hydrochloric acid ; moist- 
ened with the acid it oives a momentary bluish oreen color 
to the flame, owing to the copper that it contains, 
Diff. Distinguished from bluish-green feldspar, which 16 
resembles, by ‘its infusibility and ‘the reactions for phos- 
phorus. 
Obs. Turquois is brought from a mountainous district in 
Persia, not far from Nichabour ; and, according to Agaphi, 
occurs in veins that traverse the mountain in every direc- 
tion. 
The Callais of Pliny was probably turquois. Pliny, in 
his description of it, mentions the fable that it was found 
in Asia, projecting from the surface of inaccessib:e rocks, 
whence it was obtained by means of slings. 
Turquois receives a fine polish and is highly esteemed as 
a gem. In Persia it is much admired, and the Persian 
king is said to retain for himself all the large and more 
finely tinted specimens. The occidental or bone turquois, 
is fossil teeth or bones, colored with a little phosphate of 
iron. Green malachite is sometimes substituted for turquois, 
but it is of little hardness and has a different tint of color. 
The stone is so wellimitated by art as scarcely to be detected 
except by chemical tests. ‘The imitation is niuch softer 
than true turquois. 

Childrcnite. A hydrous phosphate containing aluminum, iron, with 
little manganese. Found in trimetric crystals in Devonshire and 
Cornwall ; also at Hebron in Maine. 
Hosphorvite. Was the crystalline form and nearly the angles of chil- 
drenite, aud contains the same constituents, but differs in being 
essentially a hydrous phosphate of manganese with little iron. Vrem 
Redding, Connecticut. 
Henwoodite is a hydrous aluminum phosphate from Cornwall, con- 
taining also copper. 
