sedimentary

Travertine / Tufa

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: Tan, brownish-red, cream, beige; Luster: Vitreous to dull/earthy; Structure: Trigonal (microcrystalline calcite); Cleavage: Perfect rhombohedral in calcite grains, but usually porous and irregular bulk structure.

Hardness: 3 on Mohs scale
Color: Tan, brownish-red, cream, beige
Luster: Vitreous to dull/earthy

Identified July 27, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms through the rapid precipitation of calcium carbonate from solution, often around geothermal hot springs, limestone caves, or alkaline lake beds. It frequently encrusts organic matter, leaving porous, spongy textures.

Uses & applications

Widely used as a decorative building stone, floor tiling, wall cladding, landscape rock, and as educational geological samples.

Geological facts

Famous structures like the Colosseum in Rome were built largely from travertine. Tufa deposits often preserve delicate plant fossils and leaf imprints coated in calcite precipitation.

Field identification & locations

Recognized by its porous, pitted texture and effervescent reaction to dilute hydrochloric acid. It can be found in limestone-rich areas and near historic or active hydrothermal vents.