mineral
Abalone Shell (Nacre)
Aragonite (CaCO3) - Biogenic Mineral
AI-generated identification · may be incorrectHardness: 3.5-4 (Mohs); Color: Iridescent blues, greens, purples, and pinks; Luster: Pearly/Iridiscent; Crystal structure: Orthorhombic (microscopic aragonite plates); Cleavage: Distinct; Specific Gravity: 2.72-2.78
- Hardness
- 3
- Color
- Iridescent blues, greens, purples, and pinks
- Luster
- Pearly/Iridiscent
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Physical properties
Hardness: 3.5-4 (Mohs); Color: Iridescent blues, greens, purples, and pinks; Luster: Pearly/Iridiscent; Crystal structure: Orthorhombic (microscopic aragonite plates); Cleavage: Distinct; Specific Gravity: 2.72-2.78
Formation & geological history
Formed by marine mollusks (genus Haliotis) through biocrystallization of calcium carbonate and conchiolin. Often categorized as a sedimentary biogenic process though the material itself is an organic mineraloid.
Uses & applications
Abalone shell is primarily used in jewelry making, inlays for musical instruments (like guitar fretboards), furniture decoration, and ritual smudging ceremonies.
Geological facts
The iridescent colors are caused by the structural interference of light waves reflecting off thin microscopic layers of aragonite, similar to the physics that gives oil on water its rainbow sheen.
Field identification & locations
Identify by its unique iridescent internal play-of-color and layered structure. It is commonly found in coastal waters of the Pacific, particularly California, South Africa, and New Zealand. Collectors look for thickness and color vibrance.
