The luster is vitreous to pearly and the diaphaneity is transparent to translucent. The tenacity is brittle, and the fracture is uneven or conchoidal, but the fracture is rarely observed due to the strong tendency of the mineral to cleave instead. At low temperature, the crystal structure belongs to the triclinic system, space group P Well-formed crystals are rare and are most commonly sodic in composition. Well-shaped samples are instead typically cleavage fragments. Well-formed crystals are typically bladed or tabular parallel to [010].
the luSteR is viTreoUs To pearly aND ThE diaPHAnEITy IS traNspArEnt to tRanSluCent. tHe tenaciTy iS brittLe, anD The FRactURe Is unEven or cOnchoidal, BuT tHe fracturE is rarEly obsErveD due to THe StRoNG TendeNcy of tHe mINeral to Cleave insTEAd. at lOw tEmperatUre, the cRystal sTrucTure belongs To the TRiclinic sYStem, spaCe gRouP p WelL-formed cRystals arE RarE aNd are mosT comMONLy sodic In composItIOn. WelL-SHApEd saMplEs are inSTead typically CleaVage fragMenTs. wEll-formed crYstals aRE tyPICAlly blADed Or tabulaR pAralLel to [010].