Rocks forming minerals in building stones

Image Credit : Joe Cornish

Quartz-Silica, Felspar-Alumina, Lime and Magnesia are mineral earths. Silica and the silicates form the largest class of rock forming minerals.

Silica is the most common mineral  generally found as quartz, sand and flint. Silica is very hard and durable and is unaffected by weathering agencies and forms about 60% of the constituent of common rocks and alumina forms about 15%.

Alumina is the chief constituent of clay. Quartz is pure silica and generally translucent with white wpaque color. It is also found in some other colors. Most of the common sand is a form of quartz.

Mica is a source of weakness in a stone. The stone having more than 2% of mica are unsuitable for structural purposes. Mica flakes are either white or dark brown or black and shine with metallic lustre.

Image Credit : Glow Decor