Diaspore, or diasporite, is an aluminium oxide hydroxide, belonging in the orthorhombic crystal system. It occurs as colourless to pinkish or yellowish lamellar crystals often with a flattened appearance. It is found in metamorphic and crystalline rocks but also in weathered clay deposits and limestones. This specimen, actual width 130 mm, is from the Kischtimsk district in the Russian Ural.