IMPORTANT ELEMENTS AND MINERALS 39 
mineral is found nearly everywhere on the surface of 
the earth, but it is particularly abundant in granitic 
Fia. 5. 
A group of quartz crystals. 
rocks, sandstone, and the great majority of - soils. 
Wherever found, it is fresh, pure silica, and in this it 
differs from many of the common minerals which are 
