3806 . DESCRIPTIONS OF MINERALS. 
makes the biscuit semi-transparent, but brittle and apt to 
break with slight changes of heat. It forms a polishing 
material for serpentine, alabaster and_ glass. “ French 
chalk” is used for removing grease-spots from cloth, as 
well as for tracing on cloth. When ground up, soapstone 
is employed for diminishing the friction of machinery. 
Pyrophyllite._-Agalmatolite, in part. 
Near tale in crystallization, cleavage, its occurrence in 
fine-grained massive forms, its greasy feel, its white to pale- 
green colors, varying to yellowish, its feeble degree of hard- 
ness (1-2). The folia are sometimes radiated. G.=2°75— 
2°92, 
Composition. An aluminous bisilicate, instead of a mag- 
nesian, for the most part of the formula, AlO,Si,. The 
Chesterfield, S. C., mineral afforded Genth, Silica 64°82, 
alumina 24°48, iron sesquioxide 0°96, magnesia 0°33, lime 
0°55, water 5°25—100°39. B.b. whitens and fuses with dit 
ficulty on the edges. Gives a deep blue color with cobalt 
solution. Yields water in the closed tube. NRadiated varie- 
ties exfoliate in fan-like forms. 
Obs. Compact pyrophyllite is the chief constituent of a 
kind of slate or schist, which is used for slate pencils, and 
henee is called pencil-stone. Occurs in the Urals; at Wes- 
tana in Sweden; in Elfdalen, with cyanite; foliated, 
North Carolina, in Cottonstone Mountain ; in South Caro- 
lina, in Chesterfield District, with lazulite and cyanite ; 
Georgia, in Lincoln County, on Graves Mountain ; in Ar- 
kansas, near Little Rock ; compact slaty in the Deep River 
region, N. C., and at Carbonton, Moore County, N. C. 
Sepiolite—Meerschaum of the Germans. 
Usually compact, of a fine earthy texture, with a smooth 
feel, and white or whitish color ; also fibrous, white to bluish- 
green in color. H.=2-2°5. The ear thy variety floats on 
water. 
Composition. 4H.3Mg 0O,Si+1faq=Silica 60°8, magnesia 
27°71, water 12°1=100. B.B. infusible, or fuses with great 
difficulty on the thin edges. Much water in a closed tube. 
A pink color with cobalt solution. 
Occurs in Asia Minor in masses in stratified earthy de- 
posits, and is extensively used for pipe bowls ; also found in 

