Sacred Precious Stone, The Amazing Chrysoberyl Cat's-eye
There are certain stones and other minerals which, owing to their possession of numerous microscopically fine cavities, of a globular or tubular shape, have the appearance of "rays" or "stars," and these are called "asteriated."
Several of such stones have been discussed already in the last chapter, and in addition to these star-like rays, some of the stones have, running through their substance, one or more streaks, perhaps of asbestos or calcite, some being perfectly clear, whilst others are opalescent.
When these streaks pass across the star-like radiations they give the stone the appearance of an eye, the rays forming the iris, the clear, opalescent, or black streak closely resembling the slit in a cat's eye, and when these stones are cut en cabochon, that is, dome-shaped, there is nothing to deflect the light beams back and forth from facet to facet, as in a diamond, so that the light, acting directly on these radiations or masses of globular cavities and on the streak, causes the former to glow like living fire, and the streak appears to vibrate, palpitate, expand, and contract, exactly like the slit in the eye of a cat.
There are a considerable number of superstitions in connection with these cat's-eye stones, many people regarding them as mascots, or with disfavour, according to their colour.
When possessing the favourite hue or "fire" of the wearer, such as the fire of the opal for those born in October, of the ruby for those born in July, etc., these stones are considered to bring nothing but good luck; to ward off accident, danger, and sudden death; to be a charm against being bitten by animals, and to be a protection from poison, the "evil eye," etc.
They figured largely, along with other valuable jewels, in the worship of the ancient Egyptians, and have been found in some of the tombs in Egypt.
They also appeared on the "systrum," which was a sacred instrument used by the ancient Egyptians in the performance of their religious rites, particularly in their sacrifices to the goddess Isis.
This, therefore, may be considered one of their sacred stones, whilst there is some analogy between the cat's-eye stones and the sacred cat of the Egyptians which recurs so often in their hieroglyphics; it is well known that our domestic cat is not descended from the wild cat, but from the celebrated cat of Egypt, where history records its being "domesticated" at least thirteen centuries B.C.
From there it was taken throughout Europe, where it appeared at least a century B.C., and was kept as a pet in the homes of the wealthy, though certain writers, speaking of the "mouse-hunters" of the old Romans and Greeks, state that these creatures were not the Egyptian cat, but a carniverous, long-bodied animal, after the shape of a weasel, called "marten," of the species the "beech" or "common" marten (mustela foina), found also in Britain to-day.
It is also interesting to note that the various superstitions existing with regard to the different varieties and colours of cats also exist in an identical manner with the corresponding colours of the minerals known as "cat's eye."
Several varieties of cat's-eye have already been described. Another important variety is that of the chrysoberyl called "cymophane."
This is composed of glucina, which is glucinum oxide, or beryllia, BeO, of which there is 19.8 per cent., and alumina, or aluminium oxide, Al2O3, of which there is 80.2 per cent. It has, therefore, the chemical formula, BeO,Al2O3.
This stone shows positive electricity when rubbed, and, unlike the sapphires described in the last chapter, which lose their colour when heated, this variety of chrysoberyl shows no change in colour, and any electricity given to it, either by friction or heat, is retained for a long time.
When heated in the blowpipe alone it remains unaltered, that is, it is not fusible, and even with microcosmic salt it requires a considerably long and fierce heat before it yields and fuses, and acids do not act upon it. It crystallises in the 4th (rhombic) system, and its lustre is vitreous.
The cymophane shows a number of varieties, quite as many as the chrysoberyl, of which it is itself a variety, and these go through the gamut of greens, from a pale white green to the stronger green of asparagus, and through both the grey and yellow greens to dark. It is found in Ceylon, Moravia, the Ural Mountains, Brazil, North America, and elsewhere.
The cat's-eye of this is very similar to the quartz cat's-eye, but a comparison will make the difference so clear that they could never be mistaken, apart from the fact that the quartz has a specific gravity considerably lower than the chrysoberyl cat's-eye, which latter is the true cat's-eye, and the one usually understood when allusion is made to the stone without any distinguishing prefix, such as the ruby, sapphire, quartz, etc., cat's eye.
It should, however, be mentioned that this stone is referred to when the names Ceylonese and Oriental cat's-eye are given, which names are used in the trade as well as the simple appellation, "cat's eye."
One peculiarity of some of these stones is that the "fire" or "glow" is usually altered in colour by the colour of the light under which it is seen, the change of colour being generally the complementary.
Thus, a stone which in one light shows red, in another will be green; the "eye" showing blue in one light will become orange in another; whilst the yellow of another stone may show a decided purple or amethyst in a different light.
A good test for this, and indeed most precious stones, is that they conduct heat more quickly than does glass, and with such rapidity that on breathing upon a stone the warmth is conducted instantly, so that, though the stone is dimmed the dimness vanishes at once, whereas with glass the film of moisture fades but slowly in comparison.
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