Almandine Garnet
The most common garnet, known for its deep red to purplish-red colors.
Physical & Optical Properties
RI Range1.770–1.830
SG Range3.93–4.30
SG Typical4.05
Hardness (Mohs)7–7.5
Crystal SystemCubic
Optic CharacterSR (Singly Refractive)
Dispersion0.024
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismNone
ColorsRed Pink, Purple, Brown
SpeciesGarnet
VarietyAlmandine
Related: Garnet Varieties
Key Differentiators
- Deep red color
- High RI and SG
- Characteristic absorption spectrum
Common Simulants
- Ruby: Ruby is doubly refractive (uniaxial negative); shows strong red fluorescence under LW UV; Chelsea filter strongly red.
- Red Spinel: Also isotropic; distinguish by RI (spinel ~1.718 vs almandine ~1.790) and fluorescence pattern.
- Red tourmaline (rubellite): Uniaxial negative DR; dichroic (red/orange-red); RI 1.624–1.644; SG 3.06.
- Glass: Isotropic; gas bubbles and swirl marks under loupe; conchoidal fracture; SG much lower.
Commonly Confused With
Commonly confused with: Ruby, Spinel, Tourmaline, glass, Pyrope Garnet, Rhodolite Garnet.
Treatments
- Fracture Filling (glass/resin)
Price Context
Natural — low ($/ct)$10
Natural — high ($/ct)$150
NotePer carat; common gem; commercial to fine quality
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
About Almandine Garnet
The most common garnet, known for its deep red to purplish-red colors.
Identifying a almandine garnet? GemID walks through these tests in order — RI, SG, fluorescence, and more.
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