Heliodor

Related: Beryl Varieties

AquamarineEmeraldGosheniteMorganiteRed Beryl

Key Differentiators

• Beryl RI and SG — separates from all yellow simulants
• Uniaxial negative — distinct from biaxial topaz and yellow sapphire
• Weak pleochroism (pale yellow / greenish-yellow)

Natural vs. Synthetic

Synthetic heliodor is commercially available (Hydrothermal). Distinguishing natural from synthetic typically requires microscopic examination of internal features.

• General Note: No commercial synthetic heliodor. Confirm beryl species: RI 1.568–1.580, SG ~2.72, uniaxial negative. Separation from simulants is via RI/SG — citrine (RI 1.544), topaz (RI 1.619–1.627), chrysoberyl (RI 1.746) all differ decisively. Synthetic: Irradiated aquamarine: blue-green beryl irradiated to yellow; same properties as natural heliodor. Irradiation origin is not detectable by standard gemological means.

Common Simulants

• Citrine: Citrine: uniaxial negative DR; RI 1.544–1.553; SG 2.65. Much lower RI than heliodor — decisive separation on refractometer.
• Yellow topaz: Topaz: biaxial positive; perfect basal cleavage; SG 3.53; RI 1.619–1.627. Higher RI, much higher SG, biaxial — all distinct from heliodor.
• Yellow chrysoberyl: Chrysoberyl: biaxial positive; RI 1.746–1.755; SG 3.70–3.78. Much higher RI and SG than heliodor.

Commonly Confused With

Commonly confused with: Citrine, Yellow Topaz, Chrysoberyl.

Treatments

• Irradiation — induces or intensifies yellow/golden color

Price Context

Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.

Measurement Guides

How to Identify a GemstoneHow to Measure Specific GravityHow to Use a RefractometerUV Fluorescence Testing