Vinogradovite

a mineral, hydrated silicate of titanium and sodium (Na₅Ti₄AlSi₆O₂₄·3H₂O). Crystallizes in a mono-clinic system, usually forming colorless, thin needlelike and fibrous aggregates, and less frequently prismatic crystals. Its hardness on the mineralogical scale is 4; its density is 2,880 kg/m³. It is widely distributed in massifs of alkaline rock. It was discovered on the Kola Peninsula by E. I. Semenov in 1956 and is named in honor of A. P. Vinogradov.