mineral

Blue Sapphire and Diamond (Set in Metal)

Corundum (Al2O3) and Diamond (C)

AI-generated identification · may be incorrect

Hardness: 9 (Sapphire) and 10 (Diamond); Color: Blue and Colorless; Luster: Adamantine to Vitreous; Crystal Structure: Trigonal and Isometric; Cleavage: None/Indistinct

Hardness: 9 (Sapphire) and 10 (Diamond)
Color: Blue and Colorless
Luster: Adamantine to Vitreous

Identified June 28, 2026More mineral →

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Physical properties

Hardness: 9 (Sapphire) and 10 (Diamond); Color: Blue and Colorless; Luster: Adamantine to Vitreous; Crystal Structure: Trigonal and Isometric; Cleavage: None/Indistinct

Formation & geological history

Sapphires form in metamorphic and igneous rocks or alluvial deposits. Diamonds form under extreme pressure and temperature in the Earth's mantle, brought to the surface by kimberlite pipes. Local geology near 47.5°N, 0.8°W (western France) includes the Armorican Massif, though these faceted gems are commercial products rather than field finds.

Uses & applications

Primary use in jewelry and as high-value gemstones; also used in industrial abrasives and precision optics.

Geological facts

Sapphire is the birthstone for September and is a variety of Corundum; any Corundum that is not red (ruby) is technically a sapphire.

Field identification & locations

Identify faceted gems by color, refractive index using a refractometer, and lack of inclusions in high-quality stones. Not typically found in the field in this processed state.