AlSiO4OH

AlSiO4OH is the chemical formula for a mineraloid known as allophane. Allophane is an amorphous hydrous aluminum silicate. It does not possess a defined crystal structure, which is characteristic of mineraloids. Its composition is variable but generally approximates Al2O3SiO2·nH2O. The presence of the hydroxyl group (OH) is a key feature. Allophane typically forms in weathered zones of aluminum-rich rocks, often as a secondary mineral. It can also be found in soils and as a deposit from hydrothermal solutions. Visually, allophane is often earthy, waxy, or clay-like in appearance and can range in color from colorless to white, gray, blue, green, or brown, depending on impurities. It is a soft mineral and is generally considered to be of little economic importance, though it can play a role in geological processes and soil formation. Its amorphous nature makes it distinct from crystalline silicates like kaolinite or quartz, which share similar elemental components but have ordered atomic arrangements.