sedimentary

Travertine (Tufa)

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: Cream, tan, or yellowish-white; Luster: Dull to earthy; Crystal Structure: Trigonal (microcrystalline); Cleavage: Perfect rhombohedral (but often obscured by porous texture); Specific Gravity: 2.3–2.7

Hardness: 3 on Mohs scale
Color: Cream, tan, or yellowish-white
Luster: Dull to earthy

Identified March 18, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by the rapid precipitation of calcium carbonate from mineral springs, particularly hot springs. The porous, sponge-like texture (Tufa) often results from the presence of organic material like moss or algae during deposition. Found in various geological ages but often associated with Quaternary deposits.

Uses & applications

Used primarily in construction as a building material, wall cladding, and flooring. Highly valued for its aesthetic rustic appearance. In smaller, more decorative forms, it is used for garden ornaments or aquascaping.

Geological facts

Famous structures like the Roman Colosseum were built primarily of travertine. The porous variety seen here is often called 'Tufa,' while the more compact, banded version used in luxury tiles is specifically called 'Travertine.'

Field identification & locations

Identify in the field by its porous, high-surface-area texture and cream color. It will react and bubble (effervesce) if a weak acid like vinegar is applied. Commonly found near limestone regions or geothermal areas like Yellowstone (USA), Italy, and Turkey.