284 DESCRIPTIONS OF MINERALS. 
Dark brown tourmalines are obtained at Orford, N. H.; 
in thin black crystals in mica at Grafton, N. H. ; Monroe, 
Ct. ; Gouverneur and Amity, N. Y. ; ; Franklin and Newton, 
N. J. A fine cinnamon-brown variety occurs at Kings- 
bridge and Amity, Orange Co., N. Y. and also south in New 
Jersey. A gray or bluish-gray ‘and green variety occurs near 
Edenville. 
The word tourmaline is a corruption of the name used in 
Ceylon, whence it was first brought to Europe. Lyncurium 
is supposed to be the ancient name for common tourmaline; 
and the red variety was probably called hyacinth. 
The red tourmalines, when transparent and free from - 
cracks, such as have been obtained at Paris, Me., are of great 
value and afford gems of remarkable beauty. ‘They have 
all the richness of color and lustre belonging to the ruby, 
though measuring an inch across. The yellow tourmaline, 
from Ceylon is but little inferior to the real topaz, and is 
often sold for that gem. The green specimens, when clear 
and fine, are also valuable for gems. Plates from pellucid 
crystals cut in the direction of a vertical plane are much 
used for polariscopes. 
Gehlenite. Tetragonal, like the scapolites, and grayish green in 
color. G.—2°9-3:07. Formula Ca,Al10,,Si, with some of the Al re- 
placed by Fe, and some of the Ca by ie and Mg. From Mount 
Monzoni in the Fassa Valley. 
Andalusite. 
Trimetric. In rhombic prisms, which are nearly square ; 
IN I=90° 48’. Cleavage lateral; sometimes distinct. Also 
massive and indistinctly coarse columnar, but never fine 
fibrous. 
Colors gray and flesh-red. Lustre vitreous, or inclining to 
vg Do Translucent to opaque. Tough. H.=7°5. c= 
ile Re 3. 
ee) A . i | 
| | mh 1+ 
HL ll HL 
Composition. AlO;Si=Silica 36:9, alumina 63°1-=100. 
B.B. infusible. Ienited after being nioiceened with cobalt 
nitrate assumes a blue color. Insoluble i in acids. 




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