sedimentary

Zebra Stone (Banded Chert or Limestone)

Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) inclusions

AI-generated identification · may be incorrect

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

Identified May 22, 2026More sedimentary →

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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.