Talc compounds?

Talc is a hydrous magnesium silicate mineral with the chemical composition Mg3Si4O10 (OH) 2. Although the chemical composition of talc usually remains close to this general formula, some substitutions do occur. A small amount of Al or Ti can replace Si, a small amount of Fe, Mn and Al can replace Mg; And very small amounts of Ca can replace Mg. When large amounts of Fe replace Mg, the mineral becomes known as Minnesota. When large amounts of Al replace Mg, the mineral is known as pyrophyllite.
Talc is usually green, white, gray, brown or colorless. Talc is a translucent mineral with a pearly sheen. Talc is the softest known mineral and has a hardness of one in the mouse hardness table.
Talc is a monoclinic mineral with a similar plate structure. Talc has a full face that forms along the plates between weakly bonded sheets. These sheets are held together by a van der Waals bond that allows them to slide freely on top of each other. This causes the talc to be very soft, soapy to the touch, greasy, and valuable as a high temperature lubricant.
Physical properties of talc
Green, white, gray, brown, colorless
Khaki white to matte green color
Pearl polish
Semi-transparent transparency
Full occurrence
Hardness one
Specific weight 2.8 to 2.7
Unique features touch, color, softness, cleavage
Monoclinic crystal system