![]() The deep colors are the most valuable, particularly a rich purple with rose flashes.Īmethysts can occur as long prismatic crystals with a six sided pyramid at either end or can form as druzes, crystalline clusters, which display mainly their numerous pointed terminations. The pale colors are sometimes called "Rose de France" and can often be seen set in Victorian jewelry. Its color is unparalleled, and even other, more expensive purple gemstones are often compared to its color and beauty.Īlthough the crystal must always be purple to be an amethyst, it can and does present a wide range of purple shades from pale lilac to deep purple. The presence of manganese in quartz produces its characteristic purple color, and additional iron content varies the coloration. The amethyst is a transparent, coarse-grained, purple variety of quartz (SiO2) and has long been the most important quartz variety used in jewelry. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.View amethysts on DesertUSA's store at Amazon If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. Some workers say that it is due to Fe+4 impurity, some say the impurity is Fe+3, and others say it is Mn. The coloring agent for amethyst is not agreed upon. ![]() Quartz can be any color: clear, white, gray, black, brown, pink, red, purple, blue, green, orange, etc. ![]() It has a glassy, nonmetallic luster, is commonly clearish to whitish to grayish in color, has a white streak, is quite hard (H≡7), forms hexagonal crystals, has no cleavage, and has conchoidal fracture. It is composed of the two most abundant elements in the crust - oxygen and silicon. Quartz (silicon dioxide/silica - SiO2) is the most common mineral in the Earth's crust. Many silicates have a significant percentage of aluminum (the aluminosilicates). All other silicates have silica + impurities. The simplest & most abundant silicate mineral in the Earth's crust is quartz (SiO2). The resulting formula for silica is thus SiO2, not SiO4. Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens "belong" to each silicon. The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4. All silicates have silica as the basis for their chemistry. ![]() The silicates are the most abundant and chemically complex group of minerals. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates. Mineral classification is based on anion chemistry. Currently, there are about 5400 named and described minerals - about 200 of them are common and about 20 of them are very common. At its simplest, a mineral is a naturally-occurring solid chemical. Description Amethyst (purple quartz) 4 (32635319682).jpgĪmethyst (= purple quartz), likely from South America.Ī mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties.
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