Burma and Siam

Rubies sometimes show on their basal planes, or on a convex surface which corresponds to the bases, a six-rayed star of gleaming light; these are called asteriated rubies, "star-rubies," or ruby cat's-eye.

So valuable are flawless rubies of good colour, that when they ascend much above a carat in weight their prices depend to a considerable extent on fancy. A three-carat ruby of desirable qualities is a rarity, while three-carat diamonds are common. Although nothing will definitely indicate what a fine ruby of three carats and upward might bring in the open market, yet Dr. George F. Kunz appraised a fine ruby of 9 5-16 carats at $33,000, and Mr. E. W. Streeter, the London jeweller and author, records a purchase price of about $50,000 for a cut ruby of 32 5/16 carats.

The common faults of rubies are lack of clearness; the presence of "clouds," also termed silk, especially in light-coloured stones; patches which resemble milk ("chalcedony patches"); internal cracks and fissures ("feathers"); and the colour being unequally distributed.

From the beginning of its history the main supply of the beautiful ruby gem has been from a small territory in upper Burma, whence, also, have come those of the finest quality. The centre of this mining region and the ruby trade is the town of Mogok, ninety miles north-north-east of Mandalay. The mining district ranges from four thousand to nearly eight thousand feet above sea-level, but, despite its altitude, this forest-covered region proves unhealthy for Europeans. The principal mines are in two valleys in which are the towns of Kathay and Kyatpyen.

Rubies and the minerals with which they are associated, such as spinel, are here found in a mother-rock of white, dolomitic, granular limestone or marble, of the upper Carboniferous age. These rocks have been altered by contact with molten igneous material which recrystallised the calcium carbonate as pure calcite, while the impurities became the ruby and its associated minerals. The precious stones are but occasionally found in the rock itself, but in an adjacent ground, which the miners call "byon," where the gem stones have weathered out; in the neighbouring river alluvium are found ruby particles, called ruby-sand. Prior to 1886 the rubies were mined by the Burmese with the primitive methods that had been in vogue for centuries, but when, in that year, Burma became part of the British Empire, the work was taken up first by an Anglo-Italian and then by an English company, which paid the Indian Government for this concession of mining rights the equivalent of about $125,000 annually.

Siam has long produced corundum rubies, but the gems are usually darker and inferior to the beautiful clear red stones from Burma. The principal mines are controlled by an English company. A few rubies have come from the gem-sands of Ceylon; a few have been found in Mysore and Madras, India; and inconsiderable products in Afghanistan and Australia. Rubies have been found in North Carolina and Montana in the United States, but the products are not of commercial importance.

Corundum rubies formed of ruby material by artificial methods have attracted attention and are cutting some figure in the jewelry trade, but they are not and can never be the peers of natural rubies; man's ingenuity and science cannot compete with Nature in the gem business. Artificial rubies are described in another chapter.