|
|||||
|
The tourmaline is a most complex substance; almost every stone obtained has a different composition, some varying but slightly, with mere traces of certain constituents which other stones possess in a perceptible degree. Consequently, it is not possible to give the chemical formula, which might, and possibly would, be found but seldom, even in [...] Considering the particular emerald which is a variety of beryl -although the name emerald in the trade is applied somewhat loosely to any stone which is of the same colour, or approaching the colour of the beryl variety -this emerald only differs chemically from the beryl, just described, in possessing an addition of oxide of [...] |
 |
|||
Copyright © 2012 Crystal and stones - All Rights Reserved |
|||||
