Tuff
Rock made of volcanic glass
Common
Volcanic ash turned to stone. Soft enough to cut with simple tools, it built the Servian Wall of Rome, the moai of Easter Island and the pink city of Yerevan. Not to be confused with tufa, a spring limestone.
Rock
- Kind of rock
- Volcanic igneous rock
- Rock family
- Volcanic rock
- Texture
- pyroclastic (volcanic ash and fragments)
- Deposits
- Volcanogenic massive sulfide deposit
- How it forms
- Ash thrown out of a vent settles and hardens; a rock of over three quarters ash is tuff.
- Uses
- The building stone of Rome, Naples and Armenia; the Romans cut it into small blocks, and decomposed tuff (pozzolana) made their cement.
Crystallography
- Habits
- Massive
Physical properties
- Luster
- Dull, Earthy
- Colors
- pink, yellow, gray, brown
- Transparency
- Opaque
Geology
- Origins
- Volcanic
- Geography
- Italy (Rome, Naples), Chile (Easter Island), Armenia, Germany (Eifel)
Classification
- Rarity
- Common
- Gem quality
- No
Sources
- Tuff. Wikipedia.
- M. R. Gillespie, M. T. Styles, BGS Rock Classification Scheme, Volume 1: Classification of igneous rocks (Research Report RR 99-06). British Geological Survey, 1999.
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