sedimentary
Seashell Fragment (Aragonite/Calcite)
Calcium Carbonate (CaCO3) - Shell fragment
Hardness: 3.0-3.5 on Mohs scale. Color: White to cream. Luster: Pearly to dull. Crystal structure: Orthorhombic (Aragonite) or Trigonal (Calcite). Specific gravity: 2.7-2.9.
- Hardness
- 3
- Color
- White to cream
- Luster
- Pearly to dull
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Physical properties
Hardness: 3.0-3.5 on Mohs scale. Color: White to cream. Luster: Pearly to dull. Crystal structure: Orthorhombic (Aragonite) or Trigonal (Calcite). Specific gravity: 2.7-2.9.
Formation & geological history
Biogenic sedimentary process. Formed as part of a marine bivalve or gastropod's exoskeleton through precipitation of minerals from seawater. This fragment has been weathered and smoothed by wave action.
Uses & applications
Shell fragments are used in soil conditioning, as a source of lime, for aquarium substrate, and in decorative jewelry or crafts.
Geological facts
While biologically produced, seashells are major contributors to the formation of limestone and marble over geological timescales. They are considered biogenic minerals.
Field identification & locations
Identify by its curved layered structure, pearly interior, and reaction (fizzing) if exposed to a mild acid like vinegar. Commonly found on coastal beaches.
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