Flipboard Magazine

Thursday, February 2, 2012

Bauxite, the Aluminum Rock

Bauxite is an aluminum ore that contains the minerals gibbsite, boehmite, and diaspore; the iron oxides goethite and hematite; and the minerals anatase and kaolinite, which is a clay. There are two types of bauxite: silicate and carbonate. Silicates are found mostly in tropical areas and carbonates are found in Europe and Jamaica. The French geologist, Pierre Berthier discovered that bauxite contained aluminum in 1821 in Les Baux, France, after which the rock is named.

Bauxite ranges from white or gray to a dark red-brown, has a dull luster, and a hardness of 1-3, which makes it unsuitable for making beads or jewelry by itself. Because bauxite is usually found near the land surface, it is usually strip mined. Bauxite production is processed into alumina, and then into aluminum by electrolysis.

Aluminum is increasingly used in jewelry making and wire work because of its relative abundance and cheaper price. It comes in many colors and wire gauges and often anodized to make it resistant to corrosion and provides a surface for better adhesion of paint primers and glues. Aluminum wire is very soft at the same gauge as nickel or brass wire, so it is better to use a lower gauge when you want a piece of jewelry to hold its shape. Sixteen, twelve, ten, or nine-gauge aluminum wire is stiffer, but thicker than another wire of the same gauge. Aluminum charms are lightweight and ideal for jewelry making.

Many jewelry suppliers now carry aluminum jewelry making supplies. I am going to try the lower-gauged aluminum the next time I buy a bunch of supplies.

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