Saturday, April 14, 2007

The Monkey Puzzle Tree: Claimed Source Of Jet

(via Gemmology Queensland, Vol.5, No.6, June 2004)

The araucaria family (Araucariaceae) contains three remarkable genera of cone-bearing trees: Araucaria, Agathis, and Wollemia. They are tall trees native to forested regions of South America and Australia. In majestic size and beauty, they certainly rival the coniferous forests of North America and Eurasia. In fact, they are considered the southern counterpart of our northern pine forests. The type genus Araucaria is derived from ‘Arauco’, a region in central Chile where the Araucani Indians live. This is also the land of the ‘monkey puzzle’ tree (A. araucana), so named because the prickly, tangled branches would be difficult for a monkey to climb. Fossil evidence indicates that ancestral araucaria forests resembling the present day monkey puzzle date back to the age of dinosaurs. In fact, it has been suggested the tree’s armor of dagger-like leaves was designed to discourage enormous South American herbivorous dinosaurs, such as Argentinosaurus weighing and estimated 80 to 100 tons. Another ancient South American species called pino parana or parana pine (A. angustifolia) grows in southern Brazil and Argentina.

Any discussion of fossilized araucariads would be incomplete without mentioning a medieval gemstone called jet. Jet is a semi-precious gem excavated in Europe and formed by metamorphosis and anaerobic fossilization of araucaria wood buried under sediments in ancient seas. Ancestral forests that metamorphosed into jet date back to the Jurassic period, about 160 million years ago. They were similar to present day forests of monkey puzzle trees (Araucaria araucana) that grow in South America. Chemically, jet is hard, carbonized form of bituminous coal with a density similar to anthracite coal. Anthracite can be readily identified by its metallic luster. Jet takes a high polish and has been used for shiny black jewelry for thousands of years. It has a specific gravity of 1.3, almost as hard as the ironwood called lignum vitae (Guaiacum officinale). Jet became very popular during the mid 19th century England during the reign of Queen Victoria, and was often worn to ward off evil spirits and during times of mourning. In the first century AD, the Roman naturalist and writer Pliny described the magical and medicinal attributes of this beautiful mineral. The well-known analogy of ‘jet’ and ‘black’ was coined by William Shakespeare in his ‘black as jet’ from Henry VI part 2. One of the most famous areas for mining of Victorian jet is Whitby on the rugged Northeast coast of England. Although they are similar in hardness, anthracite has a metallic luster and jet is dull black. Jet takes a high polish and has been used in various carved jewelry, such as cameos and intaglios. The Victoria jet broach (circa 1890) was a popular item of jewelry during the 19th century.

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