M 



NEW YORK STATE MUSEUM 



is mined in California, Wyoming and Oregon. Large deposits 

 also occur in North Carolina, Georgia, Pennsylvania and other 

 states but these deposits are not at present worked with 

 profit. 



Asbestos is extensively used for incombustible appliances and 

 fabrics. 



Crocidolite (blue asbestos) 



This is a blue to green fibrous amphibole resembling asbestos. 

 An altered form from South Africa has the interstices between 

 the fibers filled with silica and under the name of " tiger's eye " 

 is sometimes cut for a cheap gem. v 



Beryl (emerald) Be 3 Al 2 (Si0 3 ) 6 



Beryl is a silicate of beryllium and aluminium. It occurs in 

 hexagonal crystals of prismatic habit which are often striated 



Fig. 214 



Beryl 



Fig. 215 



vertically and are seldom terminated (fig. 214, 215). It is also 

 found in columnar or granular masses. The luster is vitreous 

 and the color emerald-green, pale green, light blue, yellowish 

 white, white to colorless. 



Beryl is common as an accessory mineral in granite veins. It 

 is also found in mica schist, clay slate, etc. Beryl occurs in 

 Maine, Massachusetts, New Hampshire, Connecticut, North 

 Carolina, South Dakota and other states. The finest emeralds 

 come from United States of Colombia, Brazil, India, Siberia and 

 Australia. A few emeralds have been found at Stony Point S. C. 



Emerald and a sky-blue to greenish blue variety called aqua- 

 marine are cut as gems. 



Iolite (cordierite) 



Iolite is a metasilicate of magnesium, aluminium and iron of 

 somewhat complicated formula. 



