Pinite

Fine-grained pseudomorphs after aluminosilicate minerals, especially cordierite, nepheline, topaz, andalusite, spodumene, feldspars and scapolite. Mineralogically, "pinite" is primarily composed of sericite mica (usually muscovite) and may include some clay group minerals. First reported from Pini adit, Aue, Erzgebirge, Saxony, Germany.