An alternate and widely used spelling for tainiolite was taeniolite , but now tainiolite is the official spelling. Tainiolite is a rare mica mineral. Tainiolite, like other micas, has a layered structure of lithium aluminum silicate sheets weakly bonded together by layers of potassium ions. These potassium ion layers produce the perfect cleavage. Tainiolite is easily confused with polylithionite but is comepletely non-fluorescent unlike polylithionite.
Color is colorless, tan, brown to silvery.
Luster is vitreous to pearly. Transparency crystals are transparent to translucent. Cleavage is perfect in one direction producing thin sheets or flakes. Fracture is not readily observed due to cleavage but is uneven. Hardness is 2.5 - 3.