allophane
/ˈæləˌfeɪn/
noun
- A clay-like mineral that is amorphous (non-crystalline) and often found in volcanic ash soils, usually pale blue or white.
- Geologists identified allophane in the rock samples from the volcanic region.
- Allophane gives some volcanic soils a unique ability to hold water and nutrients.
- The farmer tested the soil and found it rich in allophane from ancient ash deposits.