All About Emeralds: Composition, Color, Location, and Cutting

Composition and Hardness of Emeralds

Beryl is a mineral known to gem lovers under several different names, the most valued of which is the Emerald. The mineral beryl composing the various gems is practically the same in composition, hardness, and other properties, and the gems may be differentiated only by their color. In composition beryl is a silicate of aluminum and glucinum. On the scale of hardness beryl is graded 7 1/2 to 8, and is thus much softer than the diamond, ruby, or sapphire. It is owing to this fact that the emerald scratches easily and that care must be taken that when worn it is not subject to chafing by diamonds or other harder gems.

Color and Perfection

Beryl as a mineral is of quite common occurrence, and the crystals of the mineral in its cruder form often grow to enormous size. There is one such single crystal preserved in the Boston Museum of Natural History, which is three and one half feet long and three feet wide and weighs several tons.

Weight

Beryl in this common form occurs in many localities, but the mineral in its rarer form of emerald is comparatively of very rare occurrence. The emerald or green beryl, as it should be scientifically known, has long been the most highly prized of the green gems. In brilliancy it exceeds all other green gems excepting only the very rare green sapphire. The most valuable specimens exhibit a vivid grass-green shade, and it is to this color that they owe their great value. Other considerations, such as freedom from imperfections, are quite secondary in determining the value of the stone. In fact a perfect emerald is almost never found, and this circumstance has passed into an Eastern simile which runs, "As scarce as a perfect emerald," this being a symbol for the acme of rarity. The emerald is light in weight and an emerald of a given size will be about a third larger than a diamond and forty-five per cent larger than a sapphire of equal weight. The distinctive color of the emerald is probably due to a trace of chromium in its composition.

Where most good Emeralds are Found

The largest source of supply of fine emeralds is a mine in Muso, a locality about seventy-five miles northwest of Bogota, in the United States of Colombia. This mine has been worked almost continuously since 1558, but the wildness of the region and the barbarity of the aborigines has made the working of the mine, at least until recently, quite precarious.

Form of Cutting

Fine emeralds are generally cut cushion shape with step cutting, and in the East are often cut cabochon. Fine emeralds have advanced very rapidly during the last few years, both on account of the growing demand of fashion for the gems and the scarcity of really fine specimens.