Citrine
Last updated: April 2026
The yellow to brownish-orange variety of quartz, often created by heat treating amethyst.
Citrine has a specific gravity of 2.65 and a refractive index of 1.544–1.553, with a Mohs hardness of 7. 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: Quartz Varieties
Key Differentiators
- 'Bull's eye' optic figure
- RI and SG specific to quartz
- Most commercial citrine is heat-treated amethyst
Natural vs. Synthetic
Synthetic citrine is commercially available (Hydrothermal (same process as synthetic amethyst)). Distinguishing natural from synthetic typically requires microscopic examination of internal features.
- Color and zoning (heat-treated amethyst): Natural citrine: golden yellow to lemon, subtle layered zoning parallel to crystal faces. No purplish undertone. Synthetic: Heat-treated amethyst (most 'citrine'): reddish-brown or burnt orange hue, color concentrated near points/edges, patchy zones with residual purple. Faint tiger-stripe inclusions may remain.
- RI / SG: RI 1.544/1.553; SG ~2.65. Confirms quartz species. Synthetic: Identical for all quartz — cannot distinguish origin. Rely on color and zoning observation.
Loupewise Pro includes a two-phase natural vs. synthetic testing protocol for Citrine.
Common Simulants
- Yellow topaz: Biaxial positive DR; perfect basal cleavage; higher SG (3.53); RI 1.609–1.643.
- Yellow beryl (heliodor): Uniaxial negative DR; RI 1.577–1.583; SG 2.72; less saturated yellow typically.
Commonly Confused With
Commonly confused with: Yellow Topaz, Yellow Beryl, Heliodor, Hessonite Garnet, Spessartite Garnet, Topaz.
Treatments
- Heat-Treated Amethyst (most commercial citrine)
- Irradiation of smoky quartz
Related Comparisons
Measurement Guides
Identifying a citrine? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.
Try Loupewise Free →Studying for the GIA, FGA, or FEEG practical? Citrine 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 →