Goshenite
Last updated: April 2026
Colorless beryl. Distinguished from quartz by higher RI and hardness; from white sapphire by much lower RI and SG.
Goshenite has a specific gravity of 2.72 and a refractive index of 1.577–1.583, with a Mohs hardness of 7.5–8.0. It is uniaxial −.
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: Beryl Varieties
Key Differentiators
- RI 1.577–1.583 clearly lower than white sapphire (1.762) and white topaz (1.609–1.643)
- Higher RI than quartz (1.544–1.553) and harder (7.5–8 vs 7) — distinguishes from rock crystal
- Low dispersion (0.014) — less fire than diamond; historically used as diamond simulant
- Characteristic beryl inclusions: growth tubes, two-phase inclusions, etch channels
- SG ~2.72 — lower than most white simulants (white sapphire 4.00, white topaz 3.53)
Natural vs. Synthetic
Synthetic goshenite is commercially available (Hydrothermal). Distinguishing natural from synthetic typically requires microscopic examination of internal features.
- Microscopy: Growth tubes, two-phase inclusions, etch channels, irregular fluid fingerprints typical of natural beryl Synthetic: Hydrothermal synthetic beryl shows veil-like two-phase inclusions along growth planes (chevron pattern), nailhead spicule inclusions, and more inclusion-free zones
Loupewise Pro includes a two-phase natural vs. synthetic testing protocol for Goshenite.
Common Simulants
- Diamond: Adamantine luster, RI 2.417, SG 3.52, isotropic; thermal conductivity probe indicates diamond
- White Sapphire: Corundum RI 1.762–1.770, SG 4.00; much higher RI and density
- White Topaz: RI 1.609–1.643, SG 3.53–3.56; one perfect cleavage direction; higher RI than goshenite
- Rock Crystal (Quartz): RI 1.544–1.553, SG 2.65; lower RI and softer (7) than goshenite
- Glass: Isotropic; gas bubbles and swirl marks; variable RI typically lower than goshenite
- Cubic Zirconia: Isotropic (SR), RI 2.150–2.180, SG 5.60–6.00; much higher RI and very high SG
Commonly Confused With
Commonly confused with: Diamond, White Sapphire, White Topaz.
Treatments
- Irradiation (converts to aquamarine or heliodor)
- Heat Treatment
Measurement Guides
Identifying a goshenite? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.
Try Loupewise Free →Studying for the GIA, FGA, or FEEG practical? Goshenite 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 →