Rhodolite Garnet
Last updated: April 2026
Pyrope-almandine solid solution (~2:1 ratio) with purplish-red to raspberry-red color. RI and SG are intermediate between pyrope and almandine. No commercial synthetic exists.
Rhodolite Garnet has a specific gravity of 3.84 and a refractive index of 1.740–1.770, with a Mohs hardness of 7.0–7.5. It is singly refractive.
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: Garnet Varieties
Key Differentiators
- Distinctive purplish-red to raspberry red color
- Intermediate RI between pyrope and almandine
- Isotropic (SR) with possible ADR
- Chelsea filter inert
Common Simulants
- Ruby: Ruby: doubly refractive; strong red fluorescence; RI 1.762–1.770; Chelsea filter strongly red.
- Almandine garnet: Very similar garnet group; rhodolite RI ~1.760 vs almandine ~1.790; rhodolite more rose-red vs purple-red.
- Red-pink spinel: Spinel: isotropic; RI ~1.718; different absorption spectrum; typically less saturated.
- Glass: Isotropic; gas bubbles under loupe; conchoidal fracture; SG much lower.
Commonly Confused With
Commonly confused with: Ruby, Almandine Garnet, Spinel, Glass.
Treatments
- Fracture Filling (rare — included stones)
Measurement Guides
Identifying a rhodolite garnet? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.
Try Loupewise Free →Studying for the GIA, FGA, or FEEG practical? Rhodolite Garnet is one of the 132 species in Loupewise’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.
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