mineral

Ruby (Pink to Red Corundum)

Al2O3 (Corundum with Chromium impurities)

Hardness: 9 on the Mohs scale. Color: range from vibrant pink to deep blood-red. Luster: vitreous to sub-adamantine. Crystal structure: Trigonal (Hexagonal scalenohedral). Specific gravity: 3.97–4.05.

Hardness: 9 on the Mohs scale
Color: range from vibrant pink to deep blood-red
Luster: vitreous to sub-adamantine

Identified March 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed in metamorphic or igneous environments under high pressure and temperature. Common host rocks include marble or basaltic rocks. Geological age varies by deposit, typically ranging from 20 to 500 million years.

Uses & applications

Predominantly used as a precious gemstone in jewelry. Historically used in watchmaking (jewel bearings), and synthetic rubies are vital for laser technology and precision instruments.

Geological facts

Rubies and Sapphires are chemically identical; the presence of chromium is specifically what turns the corundum red. Historically, rubies were used as protection against misfortune and bad health in various cultures.

Field identification & locations

Field identification is done by checking the high hardness (it will scratch almost everything except diamond) and hexagonal crystal habit. Common locations include Myanmar (Burma), Sri Lanka, Madagascar, and Thailand.

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