Bauxite

(pronounced BOX-ite)
A rock consisting of aluminum oxides and hydroxides with various
impurities: the principal ore of aluminum.

What is Bauxite?
Bauxite is a rock composed mainly of aluminum oxide and aluminum hydroxide minerals. These might include: gibbsite, boehmite and diaspore. The rock usually includes other materials such as iron hydroxides, clay, silt and free silica, which means it is a sedimentary rock. It most often occurs as a residual soil material in tropical and subtropical areas. It is the primary source of aluminum.

external image Bauxite_jpg.jpgexternal image bauxite1.jpg


What is the crystal shape of bauxite?
Bauxite does not have a crystal shape, just mass.

What is it and where is it formed?
Bauxite is not a mineral, but a rock with aluminum oxide in it. Bauxite is a sedimentary rock that is an aluminum ore. It is formed in weathered volcanic rocks in a climate with high rainfall and temperature. It is the main ore of aluminum because it costs a lot of money to extract aluminum out of other ores.

What is it made of?
Bauxite is made up of about 45-60% aluminum oxide, between 15-30% water (depending on where you find the rock) and the minerals gibbsite, boehmite, and diaspore. Since it is made up of a mixture, everything varies depending on where you find it.

Where can you find It?
Bauxite is mostly mined from. It is usually mined in Australia in open-pit mines but sometimes it is mined underground. Then it is refined into alumina, and later into aluminum.There are 20 other countries that mine bauxite such as Brazil, Jamaica, and two provinces in China-Shanxi and Guizhou.

What is bauxite used for?
About 85% of all bauxite mined worldwide is used to produce alumina for refining into aluminum metal. Another 10% produces alumina wich is used in chemical, abrasive and refactory products. The remaining 5% of bauxite is used to make abrasives, refactory matrerials, and aluminum compund.



Bauxite is used to make these things:


  • Cement
  • Aluminum
  • Furnaces
external image AluminumCan.jpg


How do you identify bauxite?
Bauxite can be identified by the aluminum in it. The aluminum gives it a copper look, it has browns and colors that can be compared to a penny. It has a very unique look to it and is very easy to identify. Also, in the areas where it is mined, the ground is very reddish.
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Is Bauxite a state rock?
Bauxite is the state rock of Arkansas. It was offically called the state rock
in 1962. That is because there used to be a lot of bauxite there.
external image bauxite.jpg
(This is the bauxite rock that is located in Arkansas.)




Where did bauxite get it's name? Bauxite was first described by P. Berthier in 1821 as "alumine hydratee de beaux" which means basically fine hydrated alumina. It was then named beauxite by P.A. Dufernoy in 1847 and it wasnt until 1861 the it was officially named bauxite by Sainte Clare Dixill. Bauxite was originally located in the village of Les Boux. That is where it got it's name.

Color

white, gray, yellow, red, and dark red

Streak

normally white but may streak other colors if the specimen is stained

Luster

dull to earthy

Diaphaneity (Diaphaneity is how translucent a mineral is)

Bauxite is opaque, so it is a 0

Cleavage

because bauxite is a mixture of gibbsite, boehmite and diaspore, it has no cleavage properties of its own

Hardness

1 to 3

Specific Gravity (How dense it is compared to water)

2 - 2.5

Distinguishing Characteristics

pisolitic structure (look at definitions at bottom), color

Crystal System

Bauxite is a mixture of Diaspore (orthorhomic), Gibbsite (monoclinic), and Boehmite (orthorhombic)

Chemical Classification

oxide / hydroxide

Chemical Composition

gibbsite, Al(OH)3
boehmite, AlO(OH)
diaspore, AlO(OH)
external image thumbnail.aspx?q=409114321575&id=6b6f927feb033fe00e3354a989b94fcd
Bauxite mining in Nhulunbuy, Australia. Photo courtesy Professor Jenny Edwards, University of Technology, Sydney.
Work Citations:

Book: Pellant, Chris. Smithsonian Handbooks. second. 1098. london: dk, 1992. 253. Print.

Book:Hans-Rudolf Wenk, Andrei Bulakh. Minerals: Their constitution and origin.Cambridge: University Press, 2003. pg 526. Print.

Web site:Classic Encyclopedia(love to know)." Web. http://www.1911encyclopedia.org/Bauxite.
"Dictionary." Web. http://dictionary.com.

Web site: Pellant, Chris. "Bauxite." education foudation. N.p., 10/5. Web. 31 Dec 2010. <http://library.thinkquest.org/05aug/00461/bauxite.html

Web site: "geology on bauxite." mineral properties and uses. google, Web. <http://geology.com/minerals/bauxite.shtml>.

Web site: Lee Bray, E. "Bauxite and Alumina." statistics. N.p., n.d. Web. 2 Jan 2011. <http://minerals.usgs.gov/minerals/pubs/commodity/bauxite/>.


Definitions:

residual: [ri-zij-oo-ul]- adjective

pertaining to or constituting a residue or remainder; remaining; leftover.

diaspore[dahy-uh-spawr, -spohr] –noun

a mineral, aluminum oxyhydroxide, AlO(OH), occurring in crystals, or more usually in lamellar or scaly masses: a principal constituent of bauxite and an important source of aluminum.

pisolite [pis-uh-lahyt, piz-, pahy-suh-] –noun

limestone composed of rounded concretions about the size of a pea.

translucent [trans-loo-suhexternal image thinsp.pngnt, tranz-] –adjective

permitting light to pass through but diffusing it so that persons, objects, etc., on the opposite side are not clearly visible: Frosted window glass is translucent but not transparent.

silica [sil-i-kuh]–noun

the dioxide form of silicon, SiO 2 , occurring especially as quartz sand, flint, and agate: used usually in the form of its prepared white powder chiefly in the manufacture of glass, water glass, ceramics, and abrasives.

chiefly[cheef-lee]–adverb

primarily; essentially.