Annite is the iron rich, OH end member, of the Biotite- Phlogopite series. Common in schists, worldwide, occuring up to 3meters (!!) as crystals in granites of Cape Ann near Rockport, Mass. USA, and crystals up to 15cm from MSH (Bernard & Hrysl). Sometimes forming pseudohexagonal outlines, and foliated masses, in Mg poor igneous and metamorphc rocks.