Geographic Minerals

Euclase

Euclase

Definition – Euclase is a beryllium aluminium hydroxide silicate mineral (BeAlSiO4(OH)), that crystallizes in the monoclinic system and is typically massive to fibrous as well as in slender prismatic crystals. It is related to beryl (Be3Al2Si6O18) and other beryllium minerals. It is a product o.....

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Marcasite: Properties and Occurrences

Marcasite: Properties and Occurrences

The mineral marcasite sometimes called “white iron pyrite”, is iron sulfide (FeS2) with an orthorhombic crystal structure. It is a yellow to silvery-yellow iron sulfide mineral. It forms by precipitation from acidic waters in surface or near-surface environments. It is a polymorph of pyrite. .....

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Anhydrite

Anhydrite

Definition – Anhydrite, or anhydrous calcium sulfate, is an evaporite mineral with the chemical formula CaSO4, that occurs in extensive layered deposits in sedimentary basins where large volumes of seawater have been evaporated. It is in the orthorhombic crystal system, with three directions of.....

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Scapolite

Scapolite

Definition – Scapolite (Gr. σκάπος, rod, and λίθος, stone) any of a group of feldspathoid minerals found in calcium-rich metamorphic rocks, particularly marble, gneiss, granulite, greenschist, and skarns. It is a name used for a group of aluminosilicate minerals that includes meionit.....

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Rose Quartz

Rose Quartz

Definition – Rose Quartz, translucent, usually turbid, very coarse-grained variety of the silica mineral quartz found in pegmatites. It is the name used for pink specimens of the mineral quartz. It is abundant, common, and found in large quantities at numerous locations around the world. The pi.....

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Smoky Quartz

Smoky Quartz

Definition – Smoky Quartz is a color-variety of crystalline quartz. It is a grey, translucent variety of quartz that ranges in clarity from almost complete transparency to an almost-opaque brownish-gray or black crystal. It ranges from a light yellowish-brown to a brown that is so dark that it .....

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Manganvesuvianite: Properties and Occurrences

Manganvesuvianite: Properties and Occurrences

Manganvesuvianite is a tetragonal-dipyramidal deep maroon red mineral containing aluminum, calcium, hydrogen, iron, magnesium, manganese, oxygen, and silicon. It is a rare mineral with formula Ca19Mn3+(Al, Mn3+, Fe3+)10(Mg, Mn2+)2(Si2O7)4(SiO4)10 O(OH)9. It is a member of the vesuvianite group an.....

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Helenite

Helenite

Definition – Helenite, also known as Mount St. Helens obsidian, emerald obsidianite, and ruby obsidianite, is a trade name used for a man-made glass that is produced using volcanic ash from the 1980 eruption of Mount St. Helens. It is sold as facet rough, faceted stones, tumbled stones, and mou.....

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Fire Agate

Fire Agate

Definition – Fire Agate is a semi-precious stone that hails from the Quartz family. It is a rare and interesting gem of unusual beauty. It is a brown agate that reflects bright flashes of iridescent yellow, red, orange and green from hemispherical surfaces within the stone. These hemispherical .....

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Heliodor

Heliodor

Definition – “Heliodor” is a form of beryl, and is actually the most brilliant form of all the beryls. Heliodor is a name used by mineralogists and gemologists for specimens of the mineral beryl with a yellow, greenish yellow or golden-yellow color. Golden beryl can range in colors from pal.....

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Turquoise

Turquoise

Definition – Turquoise is an opaque mineral (blue-to-green) that is a hydrous phosphate of copper and aluminium, with the chemical formula CuAl6(PO4)4(OH)8·4H2O. It is a birthstone for the month of December, and it is an 11th Anniversary gemstone. It is rare and valuable in finer grades and ha.....

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Birthstone: Sardonyx

Birthstone: Sardonyx

Definition – “Sardonyx” is a chalcedony that it colored black, red, brown and white. This cryptocrystalline quartz can be colored with iron and carbon inclusions giving it the brown and black coloring. It is formed hydrothermally in hollows or vugs in rocks. Its name is derived from the Gre.....

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