A yellow to brownish-red mineral typically occurring as thin, elongated crystals, often in star-shaped aggregates.
Astrophyllite is a silicate of iron, titanium, manganese, and other metals, (K,Na)₃(Fe,Mn)₇Ti₂Si₈O₂₄(O,OH)₇. Crystal system: triclinic.
Mid 19th century; earliest use found in Reports of the British Association for the Advancement of Science. From astro- + -phyllite, after German Astrophyllit.