Description
Snow quartz owes its name to its pure, snow-white color. This stone is a material representation of pure white light. Quartz is a form of silicon dioxide, SiO2, and is one of the most common minerals in the Earth's crust. It represents more than 12% of the Earth's crust by volume (found in granite and sand, among other places). Quartz has two modifications: α-quartz is trigonal, and β-quartz (a higher-temperature form) is hexagonal. Silicon dioxide also occurs in many other structures, such as α- and β-cristobalite, keatite, tridymite, coesite, stishovite, melangophlogite, and lechatelierite. Although quartz consists of silicon dioxide, it is often considered a tectosilicate. This is because quartz forms a network of SiO4 tetrahedra, with each oxygen atom shared by two silicon atoms. Individual SiO2 molecules occur only in gaseous silicon dioxide. Quartz can be very pure, as with rock crystal, but often contains impurities. These impurities can consist of ions that are incorporated into the crystal lattice during crystal growth. Quartz crystals can contain between 13 and 15,000 ppm Al3+, between 9 and 1,400 ppm Na+, between 3 and 300 ppm K+, and traces of Fe3+, Ti4+, P5+, H+, and Li+. The aluminum and iron, in combination with ionizing radiation, are responsible for the color of some quartz varieties. Furthermore, quartz crystals can grow over other minerals, as is the case with rutile quartz. Quartz can form both large crystals and microscopic aggregates. The largest quartz crystals are found at Verloren Farm in Namibia. Quartz crystals up to 20 meters, and possibly 50 meters, and dolomite crystals up to 2 meters are found here. When quartz is melted, it often forms a glass upon rapid cooling, as the crystallization process takes a considerable time. Quartz is a piezoelectric material, and the vibrations that can be generated in the crystal lattice are used in electronic equipment such as quartz clocks and radios. This crystal has been known since antiquity; the ancient Greeks used pieces of quartz to cool their hands in the summer. The name quartz comes from the German "Quarz" (of Slavic origin). The Romans believed quartz was permanently solidified water (ice) because quartz was mainly found in glaciers.
