Ruby

Al2O3

This image displays a rough, deep red to pinkish-red crystal of ruby, likely opaque to translucent, possibly embedded in a matrix. It shows the characteristic hexagonal or trigonal crystal habit of corundum.

Ruby Physical Properties

Mohs Hardness

Crystal System

trigonal

Luster

vitreous

Streak Color

white

Cleavage

none (parting common)

Fracture

conchoidal

Specific Gravity

3.97

Colors

red, pinkish-red, purplish-red

Transparency

transparent

Type Locality

India, Myanmar (Burma), Thailand, Sri Lanka, Tanzania, Afghanistan

Mineral Group

Oxides

Uses

jewelry, laser technology, collector's item

Associated Minerals

kyanite, spinel, garnet, margarite, phlogopite

Rarity

rare

Geological Context

Ruby forms in metamorphic rocks such as marble, gneiss, and schist, as well as in some igneous rocks like basalt and syenite. Its red color is due to trace amounts of chromium substituting for aluminum in the crystal lattice.

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Related Specimens

Clinohumite

Greenockite

Andalusite

Diopside

Diamond

Moonstone