About the History, Sources, and Properties of Sapphires

Sapphire, the stone of April, is the symbols of constancy, truth, and virtue. Like the ruby, it is corundum, and the name "sapphire" is generally applied to corundum of any colour excepting the red. More specifically, the name is applied to blue specimens, the desired tints being royal blue, velvet blue, and cornflower blue. A characteristic of this variety of corundum is, that occasionally its colour effect by artificial light differs from that manifested in natural light, being generally less brilliant. Dealers call the blue corundums "Oriental sapphires." It is one of the most ancient of stones and its names differ but slightly in the ancient languages, Chaldean, Hebrew, Greek, and Latin, from which the English word is derived. Stones of darker colour are frequently termed male and those of lighter shades female.

Higher specific gravity and a greater degree of hardness, besides the difference in colour, distinguish the sapphire from the ruby; otherwise the sapphire's chemical and physical characteristics are generally included in the description of corundum in the foregoing chapter, covering the red corundum and other red stones termed rubies. While the form of the sapphire crystal corresponds with that of the ruby, there is a difference in the habit of crystallisation; the prism and rhombohedron of the ruby, are replaced in the sapphire by the hexagonal pyramid. The colouration of sapphires is frequently irregular; different portions of the same stone show different colours, and sometimes the body of what would be a colourless sapphire shows blue patches; but as the blue colour vanishes when the stone is heated, such a stone, undesirable as a gem, can be rendered valuable by heating it until it becomes a clear white sapphire. The colours of sapphire range from the white, colourless, or, so-called, "Leuco-sapphire"; through the yellow, called "Oriental topaz"; and through various tints to the royal blue of the typical gem sapphire. Sometimes sapphires show different colours at their terminations, as greenish-blue at one end and blue at the other, or red and blue at the ends; examples have been seen that were blue at the ends and yellow in the middle. One famous tri-coloured sapphire is cut into a figure of the Chinese sage, Confucius; the head is colourless, the body pale blue, and the legs yellow. Sapphires exhibit as many shades of blue as can be named. The very darkest, almost black, is termed "inky"; pale "feminine" stones are termed "water-sapphires"; dark, yet very blue stones, are called "indigo-sapphires," "lynx-sapphire," or "cat-sapphire." The tone and transparency of the stone are most important factors, and, provided they are present, the very dark shades are not disadvantages, although the "cornflower" is the choicest. Besides the "cornflower" colour, tones and tints are indicated by such adjectives as "Berlin," "smalt," "greyish," and "greenish." The dichroism of the sapphire is nearly always apparent if the stone is viewed from an angle that reveals it, the blue appearing tinged with green or with violet. The dichroism of the sapphire is, like that of the ruby, taken into account in producing the best effects in the cutting. In artificial light some specimens remain unchanged, while others become darker, or, perhaps, change to a reddish, purple, or violet colour. Asterias or star-sapphires present the same six-rayed gleams of light that are sometimes manifested by the ruby, but they are usually much more marked in the sapphire. Sometimes a sapphire presents but an irregular patch of opalescent light, when it is called "sapphire cat's-eye" or "Oriental girasol." Star-stones are never transparent throughout, and their cloudiness, due to enclosures of minute tabular crystals, or tiny tubular cavities, the latter in sets, is believed to cause the star-rays; the exact manner has been variously explained but not scientifically demonstrated. Star-sapphires are cut en cabochon. Sapphires being more common than rubies are less valuable.

Sapphires are found in about the same mineral situations as rubies, predominating in some localities as rubies do in others. They are more abundant than rubies in Siam, although they are mined in different localities. They are found in Ceylon, in Kashmir, in the north-west Himalaya Mountains, in the gem-gravels of Australia, and in Montana in the United States. Siam produces most of the sapphires marketed and those of the best quality. Mines at Bo Pie Rin in Battambang, Siam, yield five-eighths of the world's sapphire product. The sapphire there is found in a light sandy clay within two feet of the surface. The "mines" are small rough pits, the clay is washed away from the excavated mass, and the sapphire picked out of the residue. In America, sapphires are found at Cowee Creek in Macon County, North Carolina, where fine crystals appear in dunite, an olivine-rock. The sapphires of Montana are found in auriferous gravel in the Missouri River bed near Helena, a field of operations for placer miners for years; these miners doubtless panned out sapphires and rubies for a long time and threw them away without identifying them as precious stones. Sapphires are found at the source of the Iser River in the Iser Mountains in Bohemia in Europe; stones of the finest quality have been found there, but they have seldom exceeded four carats in weight.