Rock Identifier
Green Apatite on Albite (Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]) — mineral
mineral

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

Hardness: 5 (Apatite) and 6 (Albite); Color: Sea-green to olive greenish crystals on white/tan matrix; Luster: Vitreous to sub-resinous; Crystal Structure: Hexagonal prisms (Apatite) on triclinic blades (Albite); Cleavage: Poor; Specific Gravity: 3.1-3.2 (Apatite).

Hardness
5 (Apatite) and 6 (Albite)
Color
Sea-green to olive greenish crystals on white/tan matrix
Luster
Vitreous to sub-resinous
Identified More mineral

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Physical properties

Hardness: 5 (Apatite) and 6 (Albite); Color: Sea-green to olive greenish crystals on white/tan matrix; Luster: Vitreous to sub-resinous; Crystal Structure: Hexagonal prisms (Apatite) on triclinic blades (Albite); Cleavage: Poor; Specific Gravity: 3.1-3.2 (Apatite).

Formation & geological history

Formed in granitic pegmatites through late-stage hydrothermal processes. The apatite crystals grew upon a pre-existing matrix of bladed feldspar (cleavelandite variety of albite).

Uses & applications

Primary source of phosphorus for fertilizer in its massive form; however, crystallized specimens like this are highly valued for mineral collecting and display. Occasionally used as a gemstone, though soft.

Geological facts

Apatite is the mineral that defines index 5 on the Mohs scale of mineral hardness. It is the same material that makes up human tooth enamel and bone mineral.

Field identification & locations

Identify by the distinctive hexagonal prism shape of the green crystals and the bladed texture of the white albite. Commonly found in pegmatite districts of Brazil, Pakistan, and Maine (USA). Collectors should look for sharp crystal terminations and color clarity.