Geographic Minerals

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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Manganosite: Properties and Occurrences

Manganosite: Properties and Occurrences

Manganosite is a rare mineral composed of manganese (II) oxide MnO. It is an isometric-hexoctahedral mineral containing manganese and oxygen. It is a cubic mineral occurring as translucent green octahedral crystals that blacken on exposure to air. It was first described in 1817 for an occurrence .....

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Birthstone: Spinel

Birthstone: Spinel

Definition – “Spinel” (/spɪˈnɛl/) is a mineral that occurs in a wide variety of colors and it is a traditional birthstone for the month of August. It is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula MgAl2O4 in the cubic crystal system. Its name.....

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Birthstone: Moonstone

Birthstone: Moonstone

Definition – “Moonstone” is a sodium potassium aluminium silicate ((Na,K)AlSi3O8) of the feldspar mineral that produces a “pearly” luster when light enters the stone and is reflected by mineral layers within the gem. An alternative name is hecatolite. It is the traditional birthstone fo.....

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Birthstone: Alexandrite

Birthstone: Alexandrite

Definition – Alexandrite is a member of the chrysoberyl family of stone, some of the rarest stones on earth. It is the traditional birthstone for the month of June (along with the pearl) and the Anniversary stone for the 55th year of marriage. It is also considered Friday’s stone, or the ston.....

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Birthstone: Aquamarine

Birthstone: Aquamarine

Definition – “Aquamarine” (from Latin: aqua marina, “seawater”), is the second-most-popular gem beryl and is the birthstone for the month of March. It occurs at most localities which yield ordinary beryl. The gem-gravel placer deposits of Sri Lanka contain aquamarine. Green-yellow beryl.....

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Mother Of Pearl

Mother Of Pearl

Definition – Mother of Pearl (MOP), also known as ‘Nacre’ (/ˈneɪkər/ NAY-kər also /ˈnækrə/ NAK-rə), is a smooth shining iridescent substance forming the inner layer of the shell of some molluscs, especially oysters and abalones. It is strong, resilient, and iridescent. ‘MOP’ or .....

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