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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]
The first theme is using legendary luminous gems to illuminate buildings, for navigation lights on ships, or sometimes as guiding lights for lost persons (Ball 1938: 498–500). In India, the earliest country in which fine gemstones were known, belief in luminous gems dates back some twenty-five centuries.
A light, relatively hard yet fragile mineral, sodalite is named after its sodium content; in mineralogy it may be classed as a feldspathoid. Well known for its blue color, sodalite may also be grey, yellow, green, or pink and is often mottled with white veins or patches.
Obsidian is mineral -like, but not a true mineral because, as a glass, it is not crystalline; in addition, its composition is too variable to be classified as a mineral. It is sometimes classified as a mineraloid. [ 20] Though obsidian is usually dark in color, similar to mafic rocks such as basalt, the composition of obsidian is extremely felsic.
Epidote is an abundant rock-forming mineral, but one of secondary origin. It occurs in marble and schistose rocks of metamorphic origin. It is also a product of hydrothermal alteration of various minerals ( feldspars, micas, pyroxenes, amphiboles, garnets, and others) composing igneous rocks. A rock composed of quartz and epidote is known as ...
Siderite is a mineral composed of iron (II) carbonate (FeCO 3 ). Its name comes from the Ancient Greek word σίδηρος ( sídēros ), meaning "iron". A valuable iron ore, it consists of 48% iron and lacks sulfur and phosphorus. Zinc, magnesium, and manganese commonly substitute for the iron, resulting in the siderite- smithsonite, siderite ...
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]
Lepidolite is a phyllosilicate mineral [ 5] and a member of the polylithionite-trilithionite series. [ 6] Lepidolite is part of a three-part series consisting of polylithionite, lepidolite, and trilithionite. All three minerals share similar properties and are caused because of varying ratios of lithium and aluminum in their chemical formulas.