We are temporarily changing parts of Farlang until November 30th and apologize for any inconvenience

Close Box

Coming soon...

Ch. 12: Beryl - Garnet

Page of 311

Text size:



	230	PRECIOUS STONES.

	and the difference in colour in the various directions may sometimes be seen without the aid of the dichroscope. The green colour of the Emerald is not discharged by strongly heating, hence is not due to organic matter. Before the blowpipe even thin splinters fuse with difficulty, first turning an opaque white. The specific gravity of Beryl is 2^-67 to 2^-75. The fracture is conchoidal, and the mineral is distinctly brittle, and



	hence must be handled with care. The hardness is 7-1/2 to 8. There is an indistinct cleavage parallel to the basal plane. The streak is white. In crystalline form it is hexagonal, and the crystals usually sbow a rather slender prismatic habit (Fig. 18), and are often striated vertically by repeated oscillations of different prism faces. The Emerald in particular is very frequently seen to have numerous minute internal cracks and fissures, so that " an Emerald without a flaw " is quite

Page of 311

Table Of Contents

Annotate/ Highlight

Goodchild. Precious Stones.

Search
Books

Tag
This Page