Chrysoberyl

A relatively rare beryllium-aluminium-oxide.

Chrysoberyl shop

chrysoberyll chrysoberyl
Fine chrysoberyl from Brazil


Origin of name: from Greek χρυσός [chrysós] „gold“ and βήρυλλος [beryllos]. In ancient times the word "beryl" was used to describe many golden yellow gems.

Synonyms and trade names: none. Chrysoberyl cat´s eyes are also known as cymophan. The colourchanging variety is alexandrite.

Can be confused with: many other yellow and greenish yellow gems. Identification usually is no big deal for gemmologists.

Chrysoberyl cat´s eyes may be confused with (much cheaper) quartz cat´s eyes.

Alexandrite can be confused with other colourchanging gems like sapphire, garnet, spinel (very rare!), synthetic alexandrite and synthetic colour-change corundum.

To our knowledge (as of Jan. 2021) there is no synthetic yellow chrysoberyl.

Localities: most important sources are Brazil, India (Orissa), Sri Lanky, Mynmar (Burma) and Madagscar.

chrysoberyll chrysoberyl

Chrysoberyl from Sri Lanka

Handling: Mohs hardness of 8.5 and resistance to acids make chrysoberyl a first class gem stone. However, cleavage is distinct in one direction so, do be careful during setting. Sensitive to heat. Unset before soldering. Do not cover in Borax!

Chrysoberyl shop

Gemmological Properties of Chrysoberyl

Formula:
BeAl2O4
Crystal system:
orthorhombic
Mohs hardness:
8.5
Specific gravity:
3.69-3.81, mostly ca. 3.75
Refractive index:
doubly refractive, 1.746 - 1.756
Max. Birefringence:
0.010
Dispersion:
0.015
Pleochroism:
weak, colourless and light yellow or greenish yellow
Luminiscence:
mostly none, green (greenish) chrysoberyl: weak red
Lustre:
vitreous
Cleavage:
distinct in one direction
Fracture:
uneven, conchoidal
Colour:
yellow, greenish yellow, rarely green or brown