sedimentary
Zebra Stone (Banded Chert or Limestone)
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) inclusions
Hardness: 6.5-7 (if silica-rich), Color: Black with white or cream bands, Luster: Dull to waxy, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture)
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (if silica-rich), Color: Black with white or cream bands, Luster: Dull to waxy, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture)
Formation & geological history
Formed through the rhythmic deposition of silica-rich fluids or carbon-rich sediments in marine environments, often appearing in Precambrian or Paleozoic formations.
Uses & applications
Commonly used for lapidary work, decorative cobbles, metaphysical 'worry stones', and aquarium decor.
Geological facts
The striking contrast is often caused by alternating layers of organic-rich material (black) and pure quartz or calcite (white). These specimens are often water-worn in riverbeds to create smooth 'river rocks'.
Field identification & locations
Identify by the sharp, non-blending contrast between the black and white bands. It is frequently found in riverbeds or coastal areas where sedimentary layers have eroded.
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