Spiny Oyster Shell
What is Spiny Oyster Shell?
Spiny Oyster Shells are not true oysters, but rather a type of marine bivalve mollusk belonging to the genus Spondylus. They are known for their vibrant colors, often including shades of red, orange, yellow, and purple, and their spiny exterior. These shells are highly valued for their beauty and are used in jewelry and decorative items. They are found in various marine environments around the world.
Optical Properties
- Refractive Index
- 1.520-1.685
- Birefringence
- 0.100-0.200
- Pleochroism
- None
- Optical Character
- Biaxial negative
- Dispersion
- 0.180
Discover Values
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Spiny Oyster Shell before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Spiny Oyster Shell Localities Map
See where Spiny Oyster Shell is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Quick Facts
Physical Properties
- Color
- Red, orange, yellow, purple, white
- Hardness (Mohs)
- 3.5
- Density
- 2.71 g/cm³
- Luster
- Pearly
- Crystal System
- Amorphous
Chemical Properties
- Chemical Formula
- CaCO3
- Elements
- Ca, C, O
Also Known As

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Spiny Oyster Shell FAQs
How do I identify Spiny Oyster Shell?
Spiny Oyster Shell can be identified by its hardness of 3.5 on the Mohs scale, Red color, Pearly luster, Amorphous crystal system. Look for these key characteristics when examining specimens.
What color is Spiny Oyster Shell?
Spiny Oyster Shell typically appears in Red, orange, yellow, purple, white. Color can vary depending on impurities and formation conditions.
How hard is Spiny Oyster Shell?
Spiny Oyster Shell has a hardness of 3.5 on the Mohs scale. This gives it moderate hardness.