GEMSTONE FIELD GUIDE
Chrysoberyl
A beryllium-aluminum oxide mineral, distinct from beryl. Alexandrite is a color-change variety handled in its own record; these records are not disjoint mineral species.
Chrysoberyl hand specimen from near Greenwood, Maine, in the University of North Dakota collection.
A rough chrysoberyl-bearing hand specimen, not a faceted stone. Individual minerals in its matrix have not been identified from the photo.
Shannon Heinle / GeoDIL, University of North Dakota Mineralogy Collection #416 / CC0 · Source ↗ · CC0 1.0 · resized for the webA verified 3D specimen capture is not available for this entry. No generated stand-in is used.
AT A GLANCE
Start with the evidence.
This entry concerns non-phenomenal chrysoberyl, including yellow, brown and green stones. Alexandrite is its color-change variety; cat's-eye chrysoberyl displays chatoyancy. Neither phenomenon should be assumed from the species name, and neither variety's UV behavior is assigned to ordinary chrysoberyl here.
- Cassedanne and Roditi, Gem-A Journal of Gemmology (1993) — Chrysoberyl varieties and deposits in Brazil, pp. 333–354 ↗
- Mayerson, GIA G&G (2003) — Non-phenomenal Vanadium-Bearing Chrysoberyl, p. 144 ↗
- Refractive index (RI)
- 1.74–1.76
- Specific gravity (SG)
- 3.71–3.75
- Mohs hardness
- 8.5
rounded typical gem-material interval
How to read this value
Rounded teaching reference; a mineral sheet gives principal indices 1.746, 1.748 and 1.756. Those three listed reference indices are not measurements on a featured stone.
How to read this value
Gem-A teaching range; no artificial midpoint or specimen SG substituted.
How to read this value
Scratch resistance, not toughness. This ordinal scale is not linear.
These are reference properties, not measurements of the pictured specimen. Reference images are educational—not NumisTrends sale inventory.
See the details and limitations ↓01 · IDENTIFY
Build a profile, not a guess.
Typical material-level reference; not a measurement, identification, origin, treatment determination, or grading result for any specimen.
Refractive index (RI)1.74–1.76
rounded typical gem-material interval
Rounded teaching reference; a mineral sheet gives principal indices 1.746, 1.748 and 1.756. Those three listed reference indices are not measurements on a featured stone.
Specific gravity (SG)3.71–3.75
Gem-A teaching range; no artificial midpoint or specimen SG substituted.
Mohs hardness8.5
Scratch resistance, not toughness. This ordinal scale is not linear.
Birefringence0.008–0.010
Typical published interval, not the subtraction of population RI endpoints.
Optic characterUsually biaxial positive
Positive biaxial character is the mineral-reference classification, not a guarantee for every unusual composition.
CleavageDistinct {110}; imperfect {010}; poor {001} in the mineral reference
References disagree in practical wording: the Handbook records cleavage whereas GIA's alexandrite care page says no cleavage. Preserve that distinction rather than making an absolute species-wide absence claim.
Open a property for its scope and source. RI and specific gravity have no units. Mohs describes scratch resistance—not resistance to breaking. Do not scratch a stone to test it.
What can look similar?
Peridot
Yellow-green color can overlap; historical trade naming has also caused confusion.
How to investigate. GIA lists peridot's RI as 1.65–1.69 and birefringence as 0.035–0.038, substantially different from the cited chrysoberyl observations.
Use measured optical properties, not the color or trade name alone.
Yellow sapphire (corundum)
Yellow fragments from mixed gem deposits may resemble chrysoberyl before testing.
How to investigate. A 2016 study used Raman spectroscopy to identify yellow corundum among candidate chrysoberyl fragments.
That documented confusion concerned rough fragments; it is not a claim that every faceted yellow sapphire is difficult to distinguish.
02 · TESTS & ULTRAVIOLET
What a test can—and cannot—tell you.
Results depend on the specimen, instrument and method. This is a reference for understanding evidence, not a home authentication or treatment verdict.
UV reaction
- Long-wave UV
- One 4.29 ct non-phenomenal, vanadium-bearing green chrysoberyl examined by GIA in 2003 was inert under long-wave UV.
- Short-wave UV
- That same 4.29 ct non-phenomenal green chrysoberyl was also inert under short-wave UV.
These are one specimen's observations, not a rule for all yellow, brown or green chrysoberyl. The note does not specify numerical lamp wavelengths. No alexandrite-only or cat's-eye-only fluorescence result is transferred here.
Professional RI and optic-character examination
Whether measured optical properties support chrysoberyl rather than another yellow or green gem.
Reference observation. A Brazilian study described chrysoberyl as biaxial positive and reported approximately 1.744–1.754 across the principal indices of typical pale-yellow, golden and greenish material.
Limit. This is a study-scoped reference span, not a universal boundary or the pictured stone's result. Some samples differed; optical measurements alone do not establish natural origin.
Microscopy with laboratory confirmation when needed
Growth structures and inclusions, with Raman analysis when visual features cannot resolve mineral identity.
Reference observation. In a 2016 Australian study, Raman examination identified six small candidate fragments as yellow corundum rather than chrysoberyl.
Limit. Some fragments lacked diagnostic microscopic features. This case supports instrumental confirmation when needed, not a claim that all chrysoberyl requires Raman testing.
Real laboratory examples
Documented cases, not test results of the reference specimens shown on this page.
A mixed parcel needed instrumental checking
The 2016 Australian investigation retained 34 chrysoberyl samples after Raman testing identified six small fragments as yellow corundum.
The takeaway. A shared deposit and similar appearance do not establish that every piece has the same mineral identity.
Use a qualified gemologist for identification work. Do not expose eyes or skin to UV sources, or perform scratch, heat, acid or solvent tests on a gemstone. Do not assume that an absent UV reaction rules a material out.
03 · TREATMENTS & CARE
Protect the stone you actually have.
Disclosed treatments, fractures and settings can change which cleaning methods are appropriate.
Conservative general jewelry-care guidance, not a chrysoberyl-specific treatment assessment: use warm water, mild soap and a soft brush if the setting permits. Have a jeweler check unknown treatments and fragile settings before machine cleaning; filled fractures can make ultrasonic cleaning unsuitable.
04 · SOURCES & SCOPE
Know where each fact comes from.
Original NumisTrends explanations with primary references. This is not a replacement for gemological training, a laboratory report, or the examination of your own stone.
Properties reviewed: 2026-09-07 · Identification notes reviewed: 2026-09-07
- handbookofmineralogy.org · chrysoberyl.pdf ↗
- gem-a.com · Foundation in Gemmolgy Specifications and Syllabus.pdf ↗
- gia.edu · alexandrite care cleaning ↗
- gia.edu · WN02.pdf ↗
NumisTrends is independent of GIA, Gem-A and the museums cited. A matching property cannot by itself establish identity, natural versus laboratory-grown origin, treatment, geographic origin, grade or value.