Rock Identifier
Seashell (Calcium Carbonate) (Calcium Carbonate (CaCO3)) — mineral
mineral

Seashell (Calcium Carbonate)

Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-3.5 on Mohs scale. Color: White to cream. Luster: Pearly to dull. Structure: Orthorhombic/Hexagonal (Aragonite/Calcite ratio). Cleavage: None/Fragmentary.

Hardness
3-3
Color
White to cream
Luster
Pearly to dull
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Physical properties

Hardness: 3-3.5 on Mohs scale. Color: White to cream. Luster: Pearly to dull. Structure: Orthorhombic/Hexagonal (Aragonite/Calcite ratio). Cleavage: None/Fragmentary.

Formation & geological history

Biogenic formation through biological mineralization by marine mollusks; typically Holocene in age for modern beach finds.

Uses & applications

Used for calcium supplements, aquarium substrate, decorative crafts, and as a component in limestone sedimentary rock formation.

Geological facts

While biologically produced, seashells are composed of the minerals calcite and aragonite. Over millions of years, accumulated shells undergo lithification to become limestone.

Field identification & locations

Identify by the fan-like ribbing (costae) and bivalve shape. Common on coastal shorelines globally. High concentrations indicate marine environments.

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