Judging quality
Cat's eye quality is judged by how tight and centred the eye is and how cleanly it snaps open and shut under a single light. Glass imitations show a soft, diffuse band.
Oxide
Chrysoberyl
The third hardest gem mineral after diamond and corundum, and badly underrated. Ordinary chrysoberyl is a crisp yellow-green; the cat's eye variety cymophane shows a razor-sharp band of light from fine parallel inclusions.
Care
Extremely durable. Warm soapy water is fine.
History & lore
Sri Lankan cat's eye was a Victorian engagement stone after the Duke of Connaught gave one in 1878, briefly outrunning diamond in fashion.
Cultural history, recorded as tradition rather than as medical or scientific claim.
Common questions about Chrysoberyl
- What is Chrysoberyl?
- The third hardest gem mineral after diamond and corundum, and badly underrated. Ordinary chrysoberyl is a crisp yellow-green; the cat's eye variety cymophane shows a razor-sharp band of light from fine parallel inclusions.
- How hard is Chrysoberyl and what is it made of?
- Chrysoberyl is a Oxide-family mineral with the composition BeAl2O4. It crystallizes in the orthorhombic system and rates 8.5 on the Mohs hardness scale. It occurs in yellow-green, golden, honey.
- Where does Chrysoberyl come from?
- Notable localities for Chrysoberyl include Sri Lanka, Brazil (Minas Gerais), Madagascar, Tanzania.
- How do you tell good Chrysoberyl from filler?
- Cat's eye quality is judged by how tight and centred the eye is and how cleanly it snaps open and shut under a single light. Glass imitations show a soft, diffuse band.
- How do you care for Chrysoberyl?
- Extremely durable. Warm soapy water is fine.
See it in person
Photographs only go so far
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.