Chrysoberyl
Last updated: April 2026
A durable gemstone known for its brilliance. The cat's eye variety (cymophane) shows strong chatoyancy; faceted transparent chrysoberyl does not.
Chrysoberyl has a specific gravity of 3.73 and a refractive index of 1.746–1.755, with a Mohs hardness of 8.5. It is biaxial +.
Physical & Optical Properties
Measured with a polariscope, a refractometer, a hydrostatic balance, a Chelsea filter, a UV torch, a loupe, a darkfield loupe and a spectroscope — step-by-step for each.
Through the refractometer
Drawn from the refractive index above, on a 1.40–1.81 scale. How to take this reading.
Related: Chrysoberyl Varieties
Key Differentiators
- High hardness of 8.5
- High RI and SG
- Often very brilliant
- Cat's eye (cymophane) variety shows chatoyancy — not present in faceted stones
Common Simulants
- Yellow Sapphire: Uniaxial negative DR; RI 1.762–1.770; SG 4.00; stronger dichroism.
- Yellow topaz: Biaxial positive DR; perfect basal cleavage; RI 1.609–1.643; SG 3.53.
- Yellow zircon: Strong birefringence — visible facet doubling under loupe; high dispersion; high SG (4.67).
Commonly Confused With
Commonly confused with: Sapphire, Topaz, Zircon, Aventurine, Heliodor.
Measurement Guides
Identifying a chrysoberyl? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.
Try Loupewise Free →Studying for the GIA, FGA, or FEEG practical? Chrysoberyl is one of the 132 species in Loupewise’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.
Practice exams →