Blue Apatite

Physical Properties

Hardness: 5 on Mohs scale. Color: Deep indigo blue to teal. Luster: Vitreous to sub-vitreous. Crystal structure: Hexagonal. Specific gravity: 3.16 to 3.22.

Formation & Geological History

Formed in various geological settings including igneous pegmatites, metamorphic rocks (especially marble), and sedimentary deposits. It often forms as an accessory mineral as magma cools or during hydrothermal processes.

Uses & Applications

Used primarily as a gemstone in jewelry (though fragile), a source of phosphorus for fertilizer in agriculture, and as a popular specimen for mineral collectors.

Geological Facts

Apatite is famously used as the defining mineral for level 5 on the Mohs hardness scale. The name is derived from the Greek word 'apatein', which means 'to deceive', because it was historically confused with other minerals like tourmaline and beryl.

Field Identification & Locations

Identify by its characteristic blue color and relatively low hardness (cannot scratch glass but can be scratched by a steel knife). Commonly found in Madagascar, Brazil, Mexico, and Myanmar. Use caution when cleaning as it is sensitive to heat and acids.

Identified on: 4/13/2026

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