Sec. III, Ch. 9: Alexandrite

Sec. III, Ch. 8: True or Oriental Cat's Eye - The Chrysoberyl

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	CHAPTER IX. ALEXANDRITE.'

	HIS stone was named after the Czar of Russia, Alexander II., having been discovered on his birthday, in 1830. It owes its celebrity to its prominent hues of red and green, and as these are the military colours, the stone became much sought after in Russia. The Russian Alexandrite can rarely be shown to the best advantage in consequence of defects of structure, as it is usually flawed with crevices which make successful cutting and polishing extremely difficult. The variety found in Ceylon is more easy of manipulation. Alexandrite is especially remarkable for its strongly marked difference of colour, according as it is viewed by natural or by artificial light. The finest stones present a bright green, or deep olive green colour, by daylight ; whereas, at night, artificial light, such as that of gas or a candle, brings out a soft columbine red or raspberry tint, or purple. It has been said that the Alexandrite is an emerald by day and an amethyst at night. The Alexandrite is strongly dichroic, while some varieties are even trichroic. Chemical analysis shows that the Alexandrite is a variety of Chrysoberyl. The author has seen, in the course of his experience, two or three stones with a perfect Cat's Eye line, yet subject to the characteristic change of colour by artificial light : such stones are called Alexandrite Cat's Eyes, In order to display the line of light, it is, of course, necessary to cut the stone en cabochon instead of facetting it.

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