About the Properties and Historic Legends of Moonstones

MOONSTONES have a soft attractiveness that is in contrast with the flashing angles of the majority of precious stones. They are usually cut en cabochon or sometimes turned in the form of balls, and, as the stone is reputed to be potent in providing its possessor with good fortune, these chatoyant spheres are in favour as lucky charms. The superstitions regarding gems in medieval times included one that was quite general, that a moonstone held in the mouth would stimulate and refresh the memory. If the moonstone really possesses such efficacy, it should be a modern specific for witnesses in courts of justice, such as corporation officers whose books have been burned, or otherwise illegally disposed of, and bankrupts who cannot remember what disposition was made of their assets. Among the beliefs held of this stone, was one that it would cure epilepsy, a faith still retained by the French peasants of the Basque province. Another belief was that during the waxing of the moon it was an efficacious love charm; while during the moon's waning it would enable its wearer to foretell future events. If there is any basis in fact for this belief, it should be the favourite gem of tipsters of the race tracks and stock market.

A sort of cousin-german of the moonstone is the sunstone, which however is a far less important luminary in the firmament of gems. Although various minerals may be termed "moonstones," the true moonstone is the opalescent variety of orthoclase-feldspar, also bearing other names, but usually identified by the name adularia--a name which it derives from Mount Adula, one of the highest peaks of St. Gothard in the Alphs, where it is found. The Greeks called it Aphroseline, signifying the splendour of the moon. The Romans called it Lunaris. A transparent, fibrous, lustrous gypsum, found in England, selenite which derives its name from its soft lustre, suggestive of moonshine, and literally signifying "moonstone," may be merely mentioned here, but this soft substance is entitled to no place in a list of even the semi-precious stones.

Moonstone, according to the mineralogical concepts of the United States National Museum, is a transparent albite having a chatoyant reflection resembling that of a cat's-eye, or an opaque pearly white albite having a bluish opalescence. Albite occurs in opaque to transparent masses and in triclinic crystals having a dual cleavage in different directions, one of which is highly perfect; hardness, 6; specific gravity, 2.62; lustre vitreous, sometimes pearly on a cleavage surface; colours, white, bluish, greyish, reddish, greenish, and green, with, occasionally, a bluish chatoyancy or play of colour. One hundred parts of albite contain: silica, 68.7; alumina, 19.5; soda, 11.8.

Albite is a constituent of many crystalline rocks, and frequently replaces feldspar as a constituent of granite, of syenite, and of greenstone; sometimes it is associated with feldspar and dolomite. Common occurrences are in veins or cavities in granite or granitoid rocks, which are also sometimes repositories of fine crystals of other gem minerals, such as beryl, tourmaline, and smoky quartz.

The moonstone of commerce comes chiefly from Ceylon, where it is found in pieces several inches in diameter resulting from the decomposition of a porphyritic rock. Ceylon moonstone is sometimes erroneously termed "Ceylon opal." Albite is found at Mineral Hill, near Media, Delaware County, Pennsylvania; in Allen's Mica Mine, Amelia Court House, Virginia; and other localities in North America.