Chrysoberyl: meaning, properties, alexandrite and cat's eye

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Chrysoberyl is a beryllium aluminium oxide (BeAl2O4), hard (8.5), that is not a beryl. Its best-known varieties are alexandrite and cat's eye.

Key points

Colour	yellow, yellow-green, green, brown, grey; sometimes colour-changing (alexandrite)
Mineral family	beryllium aluminium oxide, BeAl2O4 (not a beryl)
Crystal system	orthorhombic; “trilling” twins with a hexagonal look
Hardness (Mohs)	8.5
Density	about 3.5 to 3.8
Origin of the name	Greek chrysos, “gold”, and beryl
Varieties	alexandrite (colour-changing), cat's eye (cymophane), common chrysoberyl
Known deposits	Brazil, Sri Lanka (main); Russia (Urals), India, Madagascar, Tanzania
Hardness rank	third-hardest common gemstone, after diamond and corundum

What is chrysoberyl?

Chrysoberyl is a beryllium aluminium oxide (BeAl2O4). Despite its name, it is not a beryl: beryl is a silicate (Be3Al2Si6O18), chrysoberyl an oxide, with a different structure and different properties. The name comes from Greek chrysos (“gold”), because of its golden yellow colour, and from “beryl”, by analogy.

It crystallises in the orthorhombic system, often in twins called trillings: three crystals that intergrow at 120° and form a pseudo-hexagonal star. It is very hard, 8.5 on the Mohs scale, which makes it the third-hardest common gemstone after diamond (10) and corundum (9), that is ruby and sapphire. Its density is 3.5 to 3.8.

The main deposits are in Brazil and Sri Lanka, mostly in alluvial deposits (river gravels), followed by India, Madagascar and Tanzania. The Urals, in Russia, are the historic region of alexandrite. The orthorhombic structure is also described in our mineralogy page.

Three faces of chrysoberyl

Variety	Appearance	Feature
Common chrysoberyl	yellow, yellow-green, green-yellow, clear	clear stone, cut in facets
Alexandrite	green in daylight, red-violet under incandescent light	colour change due to chromium; very rare and expensive
Cat's eye (cymophane)	yellow-green to brown, with a bright line	chatoyancy due to fine parallel needles (inclusions)

The cat's eye in the strict sense is a chrysoberyl. The same name is given to other chatoyant stones, such as the much cheaper quartz cat's eye. In the trade, always specify “chrysoberyl cat's eye” for the true gemstone.

Traditional symbolism

Common chrysoberyl, golden yellow or yellow-green, evokes the light of the sun and of gold. Modern books on crystals associate it with confidence, luck and clarity. In the Western tradition, cat's eye is a lucky charm, and in several South Asian countries it is one of the nine stones of the navaratna (associated with Ketu in Vedic astrology).

These ideas are traditions and conventions, presented as such. No study shows any effect on luck or character. In ancient texts, the word “chrysolite” designates several different yellow or green stones, including peridot and sometimes chrysoberyl: ancient texts therefore cannot serve as proof of use.

Domain	Correspondence cited
Chakra	solar plexus
Element	fire or earth, depending on the author
Vedic astrology	cat's eye: Ketu, according to Indian tradition
Keywords	confidence, clarity, brilliance

How to use it

As jewellery: ring, pendant, earrings. With a hardness of 8.5, it is one of the gems most resistant to scratches, which makes it ideal for everyday jewellery (guide).
As a cat's eye cabochon: a bright line moves as you turn the stone under a lamp.
As a collector's piece: a rough trilling is a collector's curiosity.
In meditation: watch a chatoyant line while breathing, without forcing yourself to follow it (tutorial).

Care and cleansing

Cleaning: lukewarm water, mild soap, soft brush. Dry. Chrysoberyl is hard and very stable.
Sunlight, salt, common household products: no risk to the stone itself; however, remove jewellery for housework because of the setting.
Ultrasonic cleaners and steam: generally possible for a clean stone; avoid if it is fractured.
Knocks: hard, but not unbreakable: a violent blow can chip it.
Symbolic cleansing: smoke, sound, moon (guide).

Recognising a genuine chrysoberyl

Sign	Natural chrysoberyl	Imitation or confusion
Hardness	8.5: almost impossible to scratch	apatite 5, peridot 6.5 to 7, glass 5 to 6
Weight	heavy (density 3.5 to 3.8)	light: glass or quartz
Cat's eye	fine, sharp line that stays “fixed” at the centre as the stone turns	blurred line, or glass with fibres (“glass cat's eye”)
Alexandrite	marked colour change	synthetic corundum or spinel with colour change, very common

Yellow-green chrysoberyl is confused with peridot, heliodor or apatite. Expensive alexandrite and cat's eye should be bought with a laboratory certificate. See real or fake stone and our commitments.

How to choose

Choose by colour (bright golden yellow or pale green), clarity and size. Common chrysoberyl is a hard, durable gem at a reasonable price; a fine-quality cat's eye (sharp line, honey colour) costs more; fine-quality alexandrite is very expensive. Insist on the exact variety (“chrysoberyl”), the origin and any treatments.

Pairings: with alexandrite to see the family, or with peridot for a set of greens. To look after all your stones, read our guide.