Chrysoberyl

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Chrysoberyl

Gems in the Chrysoberyl species are usually green, greenish yellow, or brown, but two varieties of Chrysoberyl are among the most rare and desirable gems in the world: Alexandrite and Cats Eye Chrysoberyl. Chrysoberyl is an 8.5 on Mohs scale, and has excellent toughness and no cleavage, making it overall a very durable stone.

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Alexandrite

Alexandrite is a rare color changing variety of Chrysoberyl. Its dual colors are a vivid green in daylight and fluorescent light, and an intense raspberry red in incandescent light. This color combination prompted the nickname “emerald by day, ruby by night.” This gem was first discovered in the Ural Mountains in Russia. The stone was named after Czar Alexander II. It is one of the birthstones for the month of June. Alexandrite can show the Cats Eye and it’s color change, but this combination is very rare.

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Cats Eye Chrysoberyl

The Cats Eye effect is caused by light reflecting from needle like fine inclusions inside the gemstone. When Cats Eye is held between two light sources and rotated, the band splits into two bands that move apart and then merge again. This effect is called “opening and closing” because it looks like an eye opening and closing. Another Cats Eye effect is known as “milk and honey”. When you look at the Cats Eye under a light source positioned perpendicular to the chatoyant band, the side nearest the light remains the original body color, but the other side displays a milky appearance. Like Alexandrite, Cats Eye is scarce.