Gems are precious stones that have been cut and polished; but in its wider meaning the term is applied generally to pearls and to those precious and semi-precious stones whose beauty and rarity cause them to be sought after as personal adornments.
Agate. An extremely hard stone found in great variety of color, the finer types, known as moss agates, being particularly striking. Brazil is richest in this type of stone.
Amethyst, a quartz found in Brazil, Australia, and Siberia.
Aquamarine, a pale-blue stone, popular in pendant form. Brazil and the Ural Mts. are its principal sources.
Beryl, green crystal related to the aquamarine.
Carnelian, a beautifully warm, red stone, of which many fine necklaces are composed. Its principal source is the Orient.
Diamond. The hardest of all precious stones, a diamond is a carbon deposit, usually in crystal form. Its great refractive power makes it the most brilliant of all gems, though in its original uncut form it is dull in appearance. Diamond-cutting is an art which dates back to the 15th century, but was not developed to any great extent before the middle of the 18th. The earliest diamonds were found in India; in the early 18th century, they began to be mined in Brazil; and in the middle of the 19th century, the first diamond was found in South Africa, which is now the greatest diamond-producing country in the world. It was a South African mine that yielded the largest diamond, the Cullinan, an enormous stone presented to King Edward VII by the Transvaal Govt. in 1907. The famous Koh-i-noor diamond is of Indian origin, and was presented to Queen Victoria by the East India Co. in 1850. The Hope diamond was blue in color.
Emerald, a variety of beryl, bright green in color. It is a very ancient stone, being valued in Egypt in Cleopatra's time. In later times it has been found in South America., Siberia, and New S. Wales. It was once believed to have medicinal qualities.
Carnet, a stone found in fairly large quantities in many countries, including Brazil, Burma, Saxony, and Bohemia. It is usually dark red, but is sometimes found in other colors.
Jade, an Asiatic stone, usually found in shades ranging from white to dark green, used as a material for carvings of various kinds, especially by the Chinese.
Lapis-lazuli, one of the most ancient of stones, blue in color, found in Peru, Afghanistan, and China.
Onyx, a stone colored in stripes or layers, black and white being a common combination. It was one of the chief and earliest stones from which cameos were cut and is obtained in India., Arabian Peninsula., and Scotland.
Opal, a stone giving a beautiful liquid color effect which changes in accordance with the movement of the stone. The fire opal seems to have a living name imprisoned in the lucent depths, but has for long had a reputation for ill-luck, Queensland, Mexico, and New S. Wales are the principal opal-producing countries.
Pearl, the smooth and shining secretion in the shell of certain oysters deposited in layers round a foreign body that has become embedded in the tissues of the mollusk. The more or less spherical object which is the form taken by this succession of layers has been eagerly sought for centuries, in many parts of the world —in the South Seas, off various parts of Australia, Ceylon, and Lower Calif. The lochs and rs. of Scot. have for long yielded pearls, and they were found in Britain at the time of the Romans. An important industry has sprung from the discovery that pearls, called culture pearls, can be artificially produced by inserting foreign bodies into the oyster.
Ruby, the most precious of precious stones. There are two main varieties, the Oriental and the Spinel, of which the first ís the more valuable. Burma is the chief ruby-producing country, but they are also to be found in Siam and Ceylon. The finest ruby is that which is set in the Imperial English crown, an enormous stone known as the Black Prince's ruby and worn by Henry V at the Battle of Agincourt.
Sapphire, a stone whose color ranges from pale to very deep blue. It is found in many parts of the world, chiefly in Siam, Burma, India, Ceylon, Australia and in the U.S.
Topaz, stone found in crystal or pebble form in Brazil, Siberia, the Ural Mts., and the Britain Isles. Its coloring varies, yellow being one of the commonest tints, but the topaz may be red, green, blue, or colorless.
Turquoise, an opaque mineral, in color blue ranging to green, found principally in Peru. The stone is often set elliptically in rings, with a convex surface, and is also used for necklaces. Its color is apt to be affected by exposure to light, and in old stones the original blue is frequently found to have become green.
