sedimentary
Banded Calcite (Onyx Marble)
Calcite (Calcium Carbonate, CaCO3)
AI-generated identification · may be incorrectHardness: 3 on Mohs scale; Color: Cream, white, and tan bands; Luster: Vitreous to waxy; Crystal Structure: Trigonal; Cleavage: Perfect rhombohedral; Specific Gravity: 2.71
- Hardness
- 3 on Mohs scale
- Color
- Cream, white, and tan bands
- Luster
- Vitreous to waxy
Identified More sedimentary →
Explore Banded Calcite (Onyx Marble) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3 on Mohs scale; Color: Cream, white, and tan bands; Luster: Vitreous to waxy; Crystal Structure: Trigonal; Cleavage: Perfect rhombohedral; Specific Gravity: 2.71
Formation & geological history
Formed through the precipitation of calcium carbonate from cold water solutions in caves (as flowstone) or around hot springs (as travertine).
Uses & applications
Commonly used for ornamental carvings, polished points, home decor, and in the metaphysical crystal market.
Geological facts
Though often commercially sold as 'Mexican Onyx' or 'Pakistan Onyx', it is a form of calcite, not true chalcedony onyx. It is soft enough to be carved with simple metal tools.
Field identification & locations
Identify by its distinct parallel banding and relative softness (can be scratched by a copper penny or steel knife). It will react and fizz if exposed to weak acid (diluted HCl).
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary