ANDALUSITE[MINERAL]

Listing Description:

Andalusite is an aluminium nesosilicate mineral with the chemical formula Al₂SiO₅.
The variety chiastolite commonly contains dark inclusions of carbon or clay which form a checker-board pattern when shown in cross-section.

Detailed Description:

A clear variety first found in Andalusia, Spain can be cut into a gemstone.^[5] Faceted andalusite stones give a play of red, green, and yellow colors that resembles a muted form of iridescence, although the colors are actually the result of unusually strong pleochroism.
It is associated with mica schist which increases alkali content in ultimate product and so it has not been exploited economically so far.

Occurrence

Andalusite is a common regional metamorphic mineral which forms under low pressure and low to high temperatures. The minerals kyanite and sillimanite are polymorphs of andalusite, each occurring under different temperature-pressure regimes and are therefore rarely found together in the same rock. Because of this the three minerals are a useful tool to help identify the pressure-temperature paths of the host rock in which they are found. An example rock includes hornfels.
It was first described and named after the type locality in the Ronda Massif, Málaga, Andalusia, Spain in 1789.

PRICE FOR ALUMINA CONTENT

$1.7/KG OR $0.77/IB

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CORUNDUM[MINERAL]

Listing dsrption

Corundum is a crystalline form of aluminium oxide (Al2O3) typically containing traces of iron, titanium, vanadium and chromium.^[2][3] It is a rock-forming mineral. It is a naturally transparent material, but can have different colors when impurities are present. Transparentspecimens are used as gems, called ruby if red and padparadscha if pink-orange. All other colors are called sapphire, e.g., green sapphire for a green specimen.

Detaild description

The name "corundum" is derived from the Tamil word Kurundam, which originates from the Sanskrit word Kuruvinda meaning ruby.^[6]

Because of corundum's hardness (pure corundum is defined to have 9.0 on the Mohs scale), it can scratch almost every other mineral. It is commonly used as an abrasive on everything from sandpaper to large machines used in machining metals, plastics, and wood. Some emery is a mix of corundum and other substances, and the mix is less abrasive, with an average Mohs hardness of 8.0.

In addition to its hardness, corundum is unusual for its density of 4.02 g/cm³, which is very high for a transparent mineral composed of the low-atomic mass elements aluminium and oxygen.

PRICE FOR ALUMINA CONTENT

$1.7/KG OR $0.77/IB

For more information:

mobile: +2348039721941

contact person: emeaba uche

e-mail: emeabau@yahoo.com

website: www.franchiseminerals.com

KYANITE(MINERAL)

LISTING DESCRIPTION

Kyanite, whose name derives from the Greek word kuanos sometimes referred to as "kyanos", meaning deep blue, is a typically blue silicate mineral, commonly found in aluminium-rich metamorphic pegmatites and/or sedimentary rock. Kyanite in metamorphic rocks generally indicates pressures higher than 4 kilobars.

DETAILED DESACRIPTION

Although potentially stable at lower pressure and low temperature, the activity of water is usually high enough under such conditions that it is replaced by hydrous aluminosilicates such as muscovite, pyrophyllite, or kaolinite. Kyanite is also known as disthene, rhaeticite and cyanite.
Kyanite is a member of the aluminosilicate series, which also includes the polymorph andalusite and the polymorph sillimanite. Kyanite is strongly anisotropic, in that its hardness varies depending on its crystallographic direction. In Kyanite, this anisotropism can be considered an identifying characteristic.
At temperatures above 1100 °C kyanite decomposes into mullite and vitreous silica via the following reaction: 3(Al₂O₃·SiO₂) → 3Al₂O₃·2SiO₂ + SiO₂. This transformation results in an expansion.^[4]

Uses of kyanite

Kyanite is used primarily in refractory and ceramic products, including porcelain plumbing fixtures and dishware. It is also used in electronics, electrical insulators and abrasives.
Kyanite has been used as a semiprecious gemstone, which may display cat's eye chatoyancy, though this use is limited by its anisotropism and perfect cleavage. Color varieties include recently discovered orange kyanite from Tanzania.^{[citation needed]} The orange color is due to inclusion of small amounts of manganese (Mn³⁺) in the structure.^[5]
Kyanite is one of the index minerals that are used to estimate the temperature, depth, and pressure at which a rock undergoes metamorphism.

Notes for identification

Kyanite's elongated, columnar crystals are usually a good first indication of the mineral, as well as its color (when the specimen is blue). Associated minerals are useful as well, especially the presence of the polymorphs of staurolite, which occur frequently with kyanite. However, the most useful characteristic in identifying kyanite is its anisotropism. If one suspects a specimen to be kyanite, verifying that it has two distinctly different hardnesses on perpendicular axes is a key to identification.

Occurrence

Kyanite occurs in gneiss, schist, pegmatite, and quartz veins resulting from moderate to high-pressure regional metamorphism of principally pelitic rocks. It occurs as detrital grains in sedimentary rocks. It occurs associated with staurolite, andalusite, sillimanite, talc, hornblende, gedrite, mullite and corundum.

PRICE FOR ALUMINA CONTENT

$1.7/KG OR $0.77/IB

For more information:

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SILLIMENITE MINERAL

Sillimanite is an alumino-silicate mineral with the chemical formula Al₂SiO₅. Sillimanite is named after the American chemist Benjamin Silliman (1779-1864). It was first described in 1824 for an occurrence in Chester, Middlesex County, Connecticut, USA.

Detailed Description:

Packaing details:

Sillimanite is one of three alumino-silicate polymorphs, the other two being andalusite and kyanite. A common variety of sillimanite is known as fibrolite, so named because the mineral appears like a bunch of fibres twisted together when viewed in thin section or even by the naked eye. Both the fibrous and traditional forms of sillimanite are common in metamorphosed sedimentary rocks. It is an index mineral indicating high temperature but variable pressure. Example rocks include gneiss and granulite. It occurs with andalusite, kyanite, potassium feldspar, almandine, cordierite, biotite and quartz in schist, gneiss, hornfels and also rarely in pegmatites.
Sillimanite has been found in Brandywine Springs, New Castle County, Delaware, USA. It was named by the State Legislature in 1977 as the state mineral of Delaware by suggestion of the Delaware Mineralogical Society, Inc.
Natural sillimanite rocks cut into the required shape and size are used mainly in glass industries. Sillimanite is the best raw material for the manufacture of high alumina refractories or 55-60% alumina bricks. But its use on large scale is not possible due to its fine grading and high cost. Dumortierite and mullite are similar mineral species used in quality porcelain.

PRICE FOR ALUMINA CONTENT

$1.7/KG OR $0.77/IB

For more information:

mobile: +2348039721941

contact person: emeaba uche

e-mail: emeabau@yahoo.com

website: www.franchiseminerals.com