gemstone

Purple Garnet

Magnesium Aluminum Silicate (Pyrope-Almandine series) Mg3Al2(SiO4)3

Hardness: 7-7.5 (Mohs scale), Color: Vivid purple to reddish-purple, Luster: Vitreous to sub-vitreous, Crystal Structure: Isometric (typically dodecahedral or trapezohedral), Cleavage: None/Indistinct, SG: 3.6-3.9

Hardness: 7-7

Identified July 18, 2026More gemstone →

Explore Purple Garnet in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed under high temperature and pressure in metamorphic rocks such as mica schists and gneisses, or as primary minerals in igneous rocks like peridotite. Common in alluvial deposits due to high weather resistance.

Uses & applications

Highly valued as a gemstone for jewelry (rings, earrings, pendants). Smaller or lower-grade specimens are used as industrial abrasives for waterjet cutting and sandblasting.

Geological facts

Purple garnets, particularly rhodolite and the rarer 'anthill' garnets, derive their color from a specific mixture of iron and magnesium. Unlike some other gems, garnets are rarely treated with heat or radiation to enhance color.

Field identification & locations

Identify by its high refractive index (strong sparkle), lack of cleavage, and isometric crystal habit. Often found in stream beds as rounded pebbles or embedded in schist matrices in regions like Idaho, USA, or East Africa.

Other gemstone specimens

See all

Diamond and Gold Jewelry

Carbon (Diamond) / Au (Gold)

gemstone

Ammolite

Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)

mineral

Cubic Zirconia (simulant) or Diamond

ZrO2 (Cubic Zirconia) or C (Diamond)

gemstone

Black Opal Ring (Carved Opal)

Hydrated Silicon Dioxide (SiO2·nH2O)

gemstone

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

sedimentary

Cubic Zirconia (or possibly Diamond)

Zirconium dioxide (or Carbon)

gemstone