Tufa
Image: José Saíz Valero (CC BY 3.0)
Mineral NameTufa
Chemical FormulaCaCO3
Mohs Hardness3
Crystal Systemtrigonal
Lusterdull
Streak Colorwhite
Cleavageperfect rhombohedral (for calcite component)
Fractureuneven to earthy
Specific Gravity2.71
Colorsreddish-brown, tan, white, cream
Transparencyopaque
Type LocalityWorldwide
Mineral GroupCarbonates
Usesbuilding material, decorative stone, soil amendment
Associated Mineralscalcite, aragonite, organic matter
Raritycommon
Description
This image displays a highly porous, sponge-like or coral-like rock with an intricate network of interconnected tubes and voids, exhibiting a reddish-brown to orange-brown color.
Geological Context
Tufa is a porous limestone formed by the precipitation of calcium carbonate from ambient temperature fresh water, typically found near springs, lakes, or waterfalls, often with significant biological influence from algae and mosses.
