sedimentary
Tufa
Calcareous Tufa (CaCO3)
AI-generated identification · may be incorrectHardness: 3-4 (Mohs); Color: Tan, beige, or grayish-white; Luster: Dull to earthy; Texture: Highly porous and vesicular with vugs; Structure: Microcrystalline calcite.
- Hardness
- 3-4 (Mohs)
- Color
- Tan, beige, or grayish-white
- Luster
- Dull to earthy
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Physical properties
Hardness: 3-4 (Mohs); Color: Tan, beige, or grayish-white; Luster: Dull to earthy; Texture: Highly porous and vesicular with vugs; Structure: Microcrystalline calcite.
Formation & geological history
Formed by the precipitation of carbonate minerals from ambient temperature water bodies, typically in freshwater lakes or near mineral springs and waterfalls. Often includes trapped organic matter.
Uses & applications
Historically used as a lightweight building stone in architecture (e.g., in Rome) and highly popular in gardening and aquarium aquascaping due to its porous nature.
Geological facts
Mono Lake in California is famous for its giant tufa towers. Tufa is often confused with travertine, but it is much more porous and forms in cooler water environments.
Field identification & locations
Identify by its light weight, 'sponge-like' appearance, and positive reaction (fizzing) to diluted hydrochloric acid. Common in karst landscapes and alkaline lakes.
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