The name 'silica' covers an entire group of minerals which have the general formula `SiO_2` , most common of which is quartz. quartz is a frame work silicate with the `SiO_4` tetrahedra arratnged in spirals . The spirals can turn in a clockwise or anti-clockwise direction - a feature that results in these being two mirror images optically active, varieties of quartz..
The silicate anion in the mineral kinoite is a chain of three `SiO_4^(-4)` tetrahedra that share corners with the adjacent tetrahdra . The mineral also contains `Ca^(2+)` ions , `Cu^(2+)` ions and water molecules in `a 1: 1: 1` ratio . This mineral is represented as :

Options

A. `CaCuSi_(3)O_(10)H_(2)O`
B. `CaCuSi_(3)O_(10)2H_(2)O`
C. `Ca_(2)Cu_(2)Si_(3)2H_(2)O`
D. None of these.

Answer

C