Talc can also be formed via a reaction between dolomite and silica, which is typical of skarnification of dolomites via silica-flooding in contact metamorphic aureoles;
Talc can also be formed from magnesian chlorite and quartz in blueschist and eclogite metamorphism via the following metamorphic reaction:
In this reaction, the ratio of talc and kyanite is dependent on aluminium content with more aluminous rocks favoring production of kyanite. This is typically associated with high-pressure, low-temperature minerals such as phengite, garnet, glaucophane within the lower blueschist facies. Such rocks are typically white, friable, and fibrous, and are known as
whiteschist.
Talc is a tri-octahedral layered mineral; its structure is similar to that of pyrophyllite, but with<unk>  in the octahedral sites of the composite layers.
Magnesium silicate
Calcium fluoride
Calcium silicate
Stannous fluoride
Aluminium hydroxide
Lithium nitride
Strontium chloride
Calcium oxide