Quartz is a very widespread mineral which occurs as an important constituent of igneous rocks which have an excess of silica. Very resistant to mechanical and chemical attack. Massive, fine grained types are called jasper, chert, flint, agate. Coarse crystalline types called amethyst, rose
quartz etc. It has the formulae SiO2 and a relative hardness of 7. During the Second World War attempts were made to synthesise quartz, and in 1947 the first optical grade crystals large enough for scientific use were grown by the hydrothermal method. Research Quartz
Quartz porphyry is a widely distributed intrusive igneous rock formed from magma in small (relatively speaking, an area of 5000 square kilometres is 'small' in geological terms) intrusive structures, such as dikes and sills, which were usually formed at no great depth. It is generally light coloured, usually grey, pink, red or violet in colour, and contains more than 65 percent silica and more than ten percent quartz, as feldspar, mica and quartz. Research Quartz Porphyry
Quartzite is a rock that occurs in two forms: sedimentary quartzite, also known as orthoquartzite; and metaquartzite which occurs as a result of sedimentary
quartzite being changed by heat. Quartzite forms from pure sands on the beds of shallow seas. Quartzite is a tough rock comprised of tightly compressed grains, and is used to make flooring and facings in the construction industry. Research Quartzite
Abbreviations
Rocks & Minerals
Research Quartz
