Geographic Minerals

Magnesioferrite: Properties and Occurrences

Magnesioferrite: Properties and Occurrences

Magnesioferrite is a magnesium iron oxide mineral, a member of the magnetite series of spinels. It is the mineral magnesium iron oxide, a member of the magnetite (q.v.) series of spinels. It is a magnetic usually black mineral MgFe2O4 consisting of an oxide of magnesium and iron and constituting .....

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Stonehenge, U.K.

Stonehenge, U.K.

Stonehenge is a prehistoric stone circle monument, cemetery, and archaeological site in Wiltshire, England, two miles (3 km) west of Amesbury. It consists of a ring of standing stones, each around 13 feet (4.0 m) high, seven feet (2.1 m) wide, and weighing around 25 tons. The stones are set withi.....

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Nazca Lines, Peru

Nazca Lines, Peru

The Nazca Lines /ˈnæzkɑː/ are a collection of giant geoglyphs designs or motifs etched into the ground located in the Peruvian coastal plain about 250 miles (400 kilometers) south of Lima, Peru. The main concentration is in a 10 by 4 km (6 mi by 2 mi) rectangle, south of San Miguel de la Pasc.....

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Deer Stones

Deer Stones

“Deer stones” (also known as ‘reindeer stones’) are a series of over 1200 ancient standing stones scattered across Mongolia and Siberia, given their name because many of them include elaborate carvings of flying deer. There are many theories to the reasons behind their existence and the p.....

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Maghemite: Properties and Occurrences

Maghemite: Properties and Occurrences

Maghemite, [Fe2O3, γ-Fe2O3] is a member of the family of iron oxides. It is a ferric oxide with a similar cubic spinel crystal structure and ferrimagnetic properties to magnetite. It has the same spinel ferrite structure as magnetite and is also ferrimagnetic. It is the ultimate low-temperature .....

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Sailing Stones

Sailing Stones

For many years, the ‘sailing stones’ of Death Valley represented one of the most curious mysteries that scientists had never been able to solve…until recently, that is. Perhaps the sailing stones kept their secret for so long because they’re so hard to reach. ‘Sailing Stones’, als.....

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Cave Of The Crystals

Cave Of The Crystals

“Cave of the Crystals” or “Giant Crystal Cave” (Spanish: Cueva de los Cristales) are the largest natural crystals known, and it has located hundreds of meters underground in Naica, Chihuahua, Mexico. The cave resembles nothing so much as an alien cathedral, with a roof propped up by huge .....

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Magadiite: Properties and Occurrences

Magadiite: Properties and Occurrences

Magadiite is a hydrous sodium silicate mineral [NaSi7O13(OH)3·4(H2O)] which precipitates from alkali brines as an evaporite phase. It is a soft white hydrous sodium silicate mineral. The mineral was first described by Hans P. Eugster in 1967 for an occurrence in Lake Magadi, Kenya, and is also f.....

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Madocite: Properties and Occurrences

Madocite: Properties and Occurrences

Madocite is a mineral with a general formula of Pb17(Sb, As)16S41. It is an orthorhombic-pyramidal grayish black mineral containing antimony, arsenic, lead, and sulfur. It is found in the marbles of the Precambrian Grenville Limestone. Madocite was named for the locality of discovery, Madoc, Onta.....

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Mackinawite: Properties and Occurrences

Mackinawite: Properties and Occurrences

Mackinawite is an iron-nickel sulfide mineral with formula (Fe, Ni)1+xS (where x = 0 to 0.11). It is a tetragonal iron-nickel sulfide mineral that occurs as opaque bronze to grey-white tabular crystals and anhedral masses. This corrosion compound is typically found in river sediment reducing envi.....

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Macdonaldite: Properties and Occurrences

Macdonaldite: Properties and Occurrences

Macdonaldite is a rare barium silicate mineral with a chemical formula of BaCa4Si16O36(OH)2·10H2O. It is an orthorhombic-dipyramidal mineral containing barium, calcium, hydrogen, oxygen, and silicon. Macdonaldite was first described in 1965 and named for Gordon A. MacDonald (1911–1978) an Amer.....

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Macaulayite: Properties and Occurrences

Macaulayite: Properties and Occurrences

Macaulayite is a red, earthy, monoclinic mineral, with the chemical formula (Fe3+, Al)24Si4O43(OH)2. It is monoclinic blood-red mineral containing aluminum, hydrogen, iron, oxygen, and silicon. The substance is currently being studied by NASA, as it is speculated that this is the substance that g.....

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