Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/47445767@N05">James St. John</a> (CC BY 2.0)
trigonalcommonCarbonates
Onyx (Cave Onyx / Mexican Onyx)
CaCO3
This image shows a whitish-colored travertine dripstone, commonly known as 'cave onyx' or 'Mexican onyx,' displaying a smooth, banded appearance typical of cave formations.
Onyx (Cave Onyx / Mexican Onyx) Physical Properties
Mohs Hardness
3Crystal System
trigonalLuster
vitreousStreak Color
whiteCleavage
perfect rhombohedralFracture
conchoidal to unevenSpecific Gravity
2.71Colors
white, cream, tanTransparency
translucent to opaqueType Locality
Crystal Onyx Cave, near Cave City, Kentucky, USAMineral Group
CarbonatesUses
decorative stone, carving, architecturalAssociated Minerals
aragonite, calciteRarity
commonGeological Context
This material is a form of travertine, composed of calcite, which precipitates from supersaturated groundwater in caves, forming speleothems within limestone and dolostone formations like the Ste. Genevieve Limestone.
