mineral

Abalone Shell (Nacre)

Aragonite (CaCO3) - Biogenic Mineral

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

Hardness: 3
Color: Iridescent blues, greens, purples, and pinks
Luster: Pearly/Iridiscent

Identified May 28, 2026More mineral →

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Physical properties

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.

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