Scratching a piece on an unglazed ceramic tile produces a white streak. Talc can be splintered into large thin sheets with a pearly luster. When held against a bright light, the sheet is either transparent or translucent with a milky background. Splintered sheets of talc are elastic but not quite as flexible as sheets of mica. Too much bend will break a sheet into two pieces.
Cleavage is perfect in one direction with an irregular fracture.
Specific gravity is 2.58 to 2.83. Talc is easy to crush into a powder. Powdered talc has a white color and is insolvent in nitric acid. When roasted in an open pan over a fire, the powder becomes very dry and flaky. When using talc as a topical medicine or internal remedy, it must first be crushed into a fine powder.