Blue Sapphire and Diamond (Set in Metal)

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

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.

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

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

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.