sedimentary

Limestone (Tufa/Travertine)

Sedimentary Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: Tan, beige, or white; Luster: Dull to earthy; Crystal structure: Trigonal (microcrystalline calcite); Specific gravity: 2.5-2.7. Often porous or vesicular in texture.

Hardness: 3 on Mohs scale
Color: Tan, beige, or white
Luster: Dull to earthy

Identified June 15, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by the precipitation of carbonate minerals from ambient temperature water bodies (tufa) or hot springs (travertine). It often forms in lacustrine, fluvial, or spring environments where evaporation or CO2 degassing occurs.

Uses & applications

Used in construction, as a building stone (travertine), in the production of lime and cement, and occasionally as decorative garden stone due to its unique weathered texture.

Geological facts

Tufa towers in Mono Lake, California, are famous examples of this rock type. It can often encapsulate organic remains like leaves or twigs, preserving their shapes as fossils.

Field identification & locations

Identify in the field by its porous, 'sponge-like' appearance and its strong effervescence when exposed to a drop of dilute hydrochloric acid. Commonly found near calcareous springs or dried lake beds.