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Amethyst. Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστος amethystos from α- a-, "not" and μεθύσκω ( Ancient Greek) methysko / μεθώ metho ( Modern Greek ), "intoxicate", a reference to the belief that the stone protected its owner from drunkenness. [ 1]
Purpurite. Purpurite is a manganese phosphate mineral with the formula MnPO 4, with varying amounts of iron depending upon its source. It occurs in color ranges from brownish black via purple and violet to dark red. [3] Purpurite forms a series with the iron-bearing endmember heterosite, FePO 4. [4]
Aquamarine variety of beryl with tourmaline on orthoclase. Arsenopyrite from Hidalgo del Parral, Chihuahua, Mexico. Aurichalcite needles spraying out within a protected pocket lined by bladed calcite crystals. Austinite from the Ojuela Mine, Mapimí, Durango, Mexico. Ametrine containing amethyst and citrine, from Bolivia.
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF 2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite.
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH −, F − and Cl − ion, respectively, in the crystal. The formula of the admixture of the three most common endmembers is written as Ca 10 ( PO 4) 6 (OH,F,Cl) 2, and the crystal unit cell formulae of the individual ...
Ochre is a family of earth pigments, which includes yellow ochre, red ochre, purple ochre, sienna, and umber. The major ingredient of all the ochres is iron (III) oxide-hydroxide, known as limonite, which gives them a yellow colour. A range of other minerals may also be included in the mixture: [ 5]: 134. Yellow ochre ( Goldochre) pigment.
Ultramarine (PB29): a synthetic or naturally occurring sulfur containing silicate mineral - Na 8–10 Al 6 Si 6 O 24 S 2–4 (generalized formula) Persian blue: made by grinding up the mineral Lapis lazuli. The most important mineral component of lapis lazuli is lazurite (25% to 40%), a feldspathoid silicate mineral with the formula (Na,Ca) 8 ...
Lepidolite is a lilac -gray or rose-colored member of the mica group of minerals with chemical formula K (Li,Al)3(Al,Si,Rb)4O10(F,OH)2. [ 2][ 3] It is the most abundant lithium -bearing mineral [ 4] and is a secondary source of this metal. It is the major source of the alkali metal rubidium .