sedimentary
Tufa
Calcareous Tufa (CaCO3)
Hardness: 3-4 (Mohs); Color: tan, grey, or white; Luster: dull to earthy; Texture: highly porous, vesicular, often with plant impressions; Cleavage: none; SG: 1.5-2.2
- Hardness
- 3-4 (Mohs)
- Color
- tan, grey, or white
- Luster
- dull to earthy
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Physical properties
Hardness: 3-4 (Mohs); Color: tan, grey, or white; Luster: dull to earthy; Texture: highly porous, vesicular, often with plant impressions; Cleavage: none; SG: 1.5-2.2
Formation & geological history
Formed by the precipitation of carbonate minerals from ambient temperature water bodies, typically near springs, lakes, or groundwater discharge areas. Often Quaternary to Holocene in age.
Uses & applications
Used as an architectural stone in building (like the Roman Colosseum), for aquarium decor, and in garden landscapes due to its porous nature.
Geological facts
Tufa is essentially a terrestrial limestone that often traps biological material like moss or twigs during formation, creating its characteristic holes.
Field identification & locations
Identify by its light weight (due to porosity), reactivity to dilute acid, and location near fresh water sources. It is often confused with its denser cousin, travertine.
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