1. plural of allophane, a hydrated aluminum silicate mineral that occurs as an amorphous clay
Usage: geology; mineralogy

Examples

• The soil samples contained significant amounts of allophanes.
• Allophanes are common in volcanic ash soils.
• The geologist identified several allophanes in the clay deposit.
• These allophanes formed through weathering of volcanic glass.
• The laboratory analysis revealed the presence of allophanes in the sediment.