GENERAL GEOLOGY

Detailed explanation-1: -In igneous rocks and pegmatites, quartz usually occurs with potassium feldspars, muscovite, biotite and amphiboles. In sedimentary rocks or metamorphosed sedimentary rocks, quartz may be associated with potassium feldspar, calcite, dolomite or a variety of clay minerals.

Detailed explanation-2: -Tennantite. Tsumeb, Otjikoto (Oshikoto) Region, Namibia. Pyramidal, slate-gray crystals of tetrahedrite have grown in and around translucent, pastel gray, crystals of quartz.

Detailed explanation-3: -Minerals are those elements on the earth and in foods that our bodies need to develop and function normally. Those essential for health include calcium, phosphorus, potassium, sodium, chloride, magnesium, iron, zinc, iodine, chromium, copper, fluoride, molybdenum, manganese, and selenium.

Detailed explanation-4: -Many varieties are gemstones, including amethyst, citrine, smoky quartz, and rose quartz. Sandstone, composed mainly of quartz, is an important building stone. Large amounts of quartz sand (also known as silica sand) are used in the manufacture of glass and ceramics and for foundry molds in metal casting.