Travertine
Travertine is a banded, often porous form of calcium carbonate that precipitates from hot springs and cave waters. It builds terraces and ledges at thermal springs and is widely used as a building stone.
Travertine is a banded, often porous form of calcium carbonate that precipitates from hot springs and cave waters. It builds terraces and ledges at thermal springs and is widely used as a building stone.
🪨 Geology Guide Specimen: Open Travertine in the CRV Science Rock & Mineral ID Guide to log the specimen, compare it with the other 6 subgroups of Sedimentary, and test your eye in LithoClade.
Degassing: How Does Warm Water Lay Down Stone?
Groundwater rich in carbon dioxide dissolves limestone at depth. When it emerges at a spring, the pressure drops and carbon dioxide escapes, so calcium carbonate precipitates as calcite or aragonite. Microbes and algae often help, and the water usually flows over rims, building stepped pools.
Terraces and Caves: Where Is Travertine Found?
Famous deposits include the terraces of Mammoth Hot Springs in Yellowstone and Pamukkale in Turkey, and the extensive travertine plains near Tivoli, Italy. Similar carbonate also forms in limestone caves as dripstone, although cave deposits are usually called speleothems.
Building Stone: Why Is Travertine Used in Rome and Beyond?
Travertine from the Tivoli quarries was used to build the Colosseum, and the Getty Center in Los Angeles is clad in Italian travertine. Its porous, banded look takes a polish and is easy to cut, and it is a close geological relative of oolitic limestone in being chemically precipitated.
Travertine at a Glance
| Property | Value |
|---|---|
| Type / variety | Banded Hydrothermal Calcium Carbonate Sinter |
| Composition | Calcite & Aragonite (CaCO₃) Precipitated by CO₂ Degassing |
| Geology Guide group | Sedimentary Rocks (Clastic, Chemical & Biogenic) |
| Rock Classification | Carbonates (Limestones & Dolostone) |
| Mohs hardness | Mohs 3–3.5 |
| Texture / habit | Porous, vuggy, or rhythmically banded crystalline layers |
| Density | 2.40–2.68 g/cm³ |
| Lustre and cleavage | Cream, tan, and honey-amber bands with elongated fenestral pores |
| Geological setting | Geothermal hot-spring terraces (e.g., Mammoth Hot Springs, Tivoli) & karst caves |
| Diagnostic feature (Geology Guide) | Banded cream, honey, and tan porous rock deposited around geothermal hot-spring terraces and karst caverns when warm groundwater rapidly loses dissolved CO₂ gas to the air. |
| Minerals | Calcite and aragonite |
| Famous uses | The Colosseum and the Getty Center |
See Also
- Oolitic Limestone — another chemically precipitated limestone
- Dolostone — a magnesium-bearing carbonate rock
- Carbonate-Silicate Cycle — the context for carbonate precipitation