Amethyst

Amethyst, a variety of Quartz (q.v.), differing from common quartz and rock-crystal chiefly in its beautiful violet-blue or purplish violet colour—well known as amethystine—which is owing to the presence of a little peroxide of iron or of manganese. It is one of the most esteemed varieties of quartz, and is much employed for seals, rings, &c., although, being comparatively abundant, it is much inferior in price to the true gems. An amethystine tinge is frequently to be observed in specimens of quartz, which yet are not perfect amethyst. The tinge is often very faint, and is frequently confined to the summits or edges of the crystals. The finest specimens of amethyst are brought from India, Ceylon, and Brazil. It is, however, a common mineral in Europe, and occurs in many parts of Scotland. It frequently occurs lining the interior of balls or geodes of agate, and in veins and cavities in basalt, diabase, and other igneous rocks. The ancients imagined it to possess the property of preventing intoxication, and persons much addicted to drinking therefore wore it on their necks. The name is derived from a Greek word which signifies unintoxicated.—Not to be confounded with this mineral is that sometimes called the oriental amethyst, which is a variety of Spinel (q.v.) having an amethystine colour, and is a very valuable gem. False amethysts made of glass or paste are very common, and in general very coarse; but a very perfect imitation can be and sometimes is made.