Chemical Formula: Mg3Si4O10(OH)2
Color: Usually white or grey, but may also have a tint of green
Importance: Powdered talc is made into talcum powder, which is used in cosmetics and baby powder. Due to its resistance to heat and electricity, it is often used as a resistor. Also found in paints and rubbers.
Other Interesting Information: Due to its low hardness, talc can be scratched by nearly anything, including your fingernail. Inhalation of large amounts of powdered talc is known to cause respiratory problems.
My Take: Talc is just weird. Just by looking at it and feeling it, it does not look very soft at all, any yet it can be scratched by just about anything. It doesn’t make too much sense.
For More Information: http://www.minerals.net/mineral/talc.aspx