mineral
Mother of Pearl (Nacre)
Aragonite (layered with organic polymers), CaCO3
AI-generated identification · may be incorrectHardness: 3.5-4.5 (Mohs); Color: White, cream, or iridescent silvery-white; Luster: Pearly to iridescent; Crystal Structure: Orthorhombic (as aragonite platelets); Cleavage: None; Specific Gravity: 2.7-2.8
- Hardness
- 3
- Color
- White, cream, or iridescent silvery-white
- Luster
- Pearly to iridescent
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Physical properties
Hardness: 3.5-4.5 (Mohs); Color: White, cream, or iridescent silvery-white; Luster: Pearly to iridescent; Crystal Structure: Orthorhombic (as aragonite platelets); Cleavage: None; Specific Gravity: 2.7-2.8
Formation & geological history
Biogenic formation; produced by certain mollusks as an inner shell layer. It is formed by the secretion of thin, alternating layers of aragonite and conchiolin (a protein) by the mantle tissue of the organism. This specimen is modern (Holocene).
Uses & applications
Primarily used in jewelry (beads, pendants), watch faces, musical instrument inlays, furniture marquetry, and high-end button manufacturing.
Geological facts
The iridescent 'orient' of mother of pearl is caused by the interference of light as it reflects off thin, overlapping microscopic layers of aragonite. It is chemically identical to the pearl itself.
Field identification & locations
Identify in the field by its distinct iridescent 'shimmer' that changes when rotated under light, and a hardness that is significantly lower than quartz or glass. Commonly harvested from pearl oysters, freshwater mussels, and abalone found in both marine and freshwater environments worldwide.
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