Almandine Garnet

← Back to Reference Database RI Chart SG Chart Fluorescence Hardness

Almandine Garnet has a specific gravity of 4.05 and a refractive index of 1.770–1.830, with a Mohs hardness of 7.0–7.5. It is singly refractive.

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

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. Loupewise is not an appraisal tool. Results are indicators, not certified valuations.

Measurement Guides

Identifying an almandine garnet? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.

Try Loupewise Free →

Studying for the GIA, FGA, or FEEG practical? Almandine Garnet is one of the 130 species in Loupewise’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.

Practice exams →