(1) In the line rock, this black tourmaline occurs as tiny prismatic crystals.(2) Inclusions of quartz, tourmaline , apatite, and muscovite crystals have been described.(3) The mineral assemblage comprises quartz, K-feldspar, albitic plagioclase, white mica, apatite, tourmaline and garnet.(4) After quartz and microcline, tourmaline is arguably the next most abundant mineral found in the miarolitic cavities.(5) It consists of clasts of angular to rounded quartz, plagioclase, tourmaline and rock fragments, up to 3 mm in diameter.