148 



MAGNESIA. 



meerschaum. — Sea Froth. 



Dull white, opaque and earthy, nearly like clay. H=2 

 Gr=2-6— 3-4. 



Composition of a variety from Anatolia : silica 60*9, mag. 

 ne<*ia 278. water 113, oxyd of iron anH alumina 0*1 

 When heated it gives out water and a fetid odor, and be- 

 comes hard and perfectly white. When first dug up it is 

 soft, has a greasy feel and lathers like soap ; and on this 

 account it is used by the Tartars in washing their linen. It 

 ,is used for making the bowls of Turkish pipes, by a process 

 like that for pottery ware. When imported into Germany, 

 the bowls of the pipes are prepared for sale by softening 

 them first in tallow, then in wax, and finally polishing them. 



Aphrodite is another meerschaum from Longbanshyttan. 



Quincite is a variety or related species of a reddish color. 



SCHILLER SPAR. 



Triclinic. Occurs massive, with cleavage in two direc- 

 tions, producing a thin foliated structure. Folia brittle and 

 separable. Color olive and blackish-green, inclining on the 

 cleavage face to pinchbeck-brown. Luster metallic-pearly 

 on a cleavage face ; vitreous in other directions. H =3-5 — 

 4. Sectile. Gr = 2'5— 2*7. 



Composition : silica 43*9, magnesia 25*9, oxyd of iron and 

 chromium 13*0, water 12*4, alumina 1*3, lime 2*6, protoxyd 

 of manganese 0'5. Gives off water, and becomes pinch- 

 beck-brown and magnetic before the blowpipe, but fuses 

 only on the thinnest edges. 



Dif. Distinguished from diallage, which also occurs in 

 serpentine, and is the only species with which it can be 

 confounded, by its yielding water before the blowpipe. 

 Marmolite is much softer. Talc and mica are flexible. 



Obs. Occurs imbedded in serpentine. Baste in the Hartz 

 is a foreign locality. Blandford and Westfield, Mass., and 

 Amity, N. Y., are given as American localities. 



Clintonite. In oblique crystals : but usually massive, thin foliated, 

 and brittle, with a submetallic luster, and reddish or yellowish- brown, 

 or copper-red color. Streak yellowish-gray. Composition, silica 17 - 0, 

 alumina 37 - 6, magnesia 243, lime 10-7, protoxyd of iron 5-0, water 



What is meerschaum 1 its appearance ? What is the structure of 

 Schiller spar 1 its luster 1 What does it occur with ? How does if 

 differ from diallage? 



