Rock crystal from Madagascar chunks rough 2-5 centimeters. Sales per kilogram.

Rock crystal is the colorless and most common variant of the mineral quartz (silicon dioxide, SiO2). The name 'rock crystal' is derived from the Greek word "Krustallos" which means ice. It was believed that rock crystal was ice shaped by the gods. Rock crystal was already known at the time of the Mesolithic. During Roman times it was brought onto the market from the Alps under the name "petrified ice". Theophratus called it "krystallos". Pliny the Elder also mentions it. The name "quartz" was introduced in 1529 by Georgius Agricola. The peoples of the East regarded rock crystal as a stone of patience and perfection. Tibetans use rock crystal to treat wounds. The choice of rock crystal as a drinking glass or as part of medieval jewelry can be are attributed to the belief that these crystals would break or discolor when they came into contact with poison. Thus the chain became an amulet that protected the king. Compare the Rudolfinian imperial crown and the chain of the Jehovah Order. Origin: Megnatites, pegmatites, hydrothermal and alpine stone veins, alluvial deposits. Occurrence: Rock crystal is widely distributed in nature, but not always in gemstone quality. Historically known sites are India and Sri Lanka (the Tatnaputi area). Iridescent quartz from the Poona area in India and from Myanmar is a rarity. Beautiful crystals come from Kenya and Madagascar, also from Brazil (Minas Gerais), Goisas, Bahia and French Guiana. In the US, rock crystal occurs in pegmatites, including in Maine (near Ausburn, New York, North Carolina, Arkansas (Crystal Peak) and California. Of particular importance are occurrences in the Alps. Rock crystals are found in Switzerland (for example near Urim, where a crystal weighing 135 kg has been found in the area of Sint-Gotthard and Grimsel), in Austria (in 1965 a crystal weighing almost 1000 kg was found in a cavity near the Großglockner). Rock crystals are also found in Germany, the Czech Republic , Poland and France. The collections of various museums contain unique cut rock crystals. The Smithsonian Institution Washington has a cut stone of 7000 kt and a convex rock crystal with a diameter of 33 cm and a weight of 48.5 kg; this comes from Burma and was cut in China.