Feldspar is a common type of rock-forming mineral that makes up about 60% of the Earth's crust. It is widely used in industry and construction due to its hardness and resistance to weathering. Feldspar comes in a variety of colors and is a key component in ceramics, glass, and pottery.
By the hydration of silicon dioxide: SiO 2 + 2 H 2O → SiH 4O 4.
Chalk is a sedimentary rock composed primarily of Calcium Carbonate. Calcium carbonate is also the number one mineral at the Marble spec. Hardness of Chalk is around 3 Mohs. Granite stay at the number 7 at the Mohs scale and Granite is harder than Marble. Granite is mostly composed by feldspat (christal).