A compact, granular, metamorphosed sandstone containing quartz. Colour: white, red, brown or grey. May be shipped in semi-crushed and graded sizes. Bulk density: 1,563 kg/m3. Non-IMSBC Code information: Moisture IS under 1%. It is formed by the deposit of secondary silica between the original grains so that the rock is more firmly cemented and less porous than the original sandstone. Quartzite is much harder than the parent rock, sandstone. The best way to tell the difference between quartzite and sandstone is to break the rocks. Quartzite can break through the grains whereas sandstone will shatter into many individual grains of sand. Used as a valuable construction aggregate, e.g. in road construction, due to its hardness, non-porosity (i.e., absorbs little or no moisture).