BAHIA BELT

Turquoise, the gemstone worn by pharaohs and Aztec kings, is probably one of the oldest gemstones known. Native Americans and many of the Indian tribes in Mexico used turquoise for currency, and the stone is still associated with the religious rites of the Navajo. Because it remains fashionable, turquoise is quite highly prized, although it is fairly plentiful.

An alloy of copper and zinc, brass is usually yellow in color, therefore sometimes mistaken for gold. Some types of brass are called bronzes, despite their high zinc content.

Brass has been known to man since prehistoric times, long before zinc itself was discovered. It was produced by melting copper together with calamine, a zinc ore. During this process, the zinc is extracted from the calamine and instantly mixes with the copper. Pure zinc, on the other hand, is too reactive to be produced by ancient metalworking techniques.

Vegetable tanning is "a generic term to cover the process of making leather by the use of tannins obtained from barks, woods or other parts of plants and trees, as distinguished from "mineral tannages".

The most important organic tanning agents are the vegetable tannins present in tanning liquors. They are prepared from certain parts of plants by aqueous extraction. Their tanning power has been appreciated for a long time and Babylonian texts have recorded their use.