Amber
In 1992, scientists reveal oldest genetic material, a 40-million-year old bee, preserved in this yellow ooze.
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Amber is a yellow transparent or translucent fossilized material formed from resin that oozed from trees many thousands or millions of years ago. It is sometimes tinted red, orange, or brown, and may be clouded by minuscule air bubbles. Trees exude resin for many reasons, among them to combat disease, seal wounds, and prevent attack by insects. The material is initially sticky, but on exposure to light and air, most resins tend to harden into solid masses that are resistant to normal decay processes. Pieces of amber often survive, buried in soils or sediments, for millions of years, yielding invaluable scientific information about the history of life on Earth.
Natural resins such as amber generally consist of mixtures of organic compounds, including alcohols, ketones, carboxylic acids, and most notably, unsaturated hydrocarbons known as terpenes and related terpenoid compounds. Monoterpenes, isomers with the formula C10H16, consist of two isoprene units [CH2=C(CH3)CH=CH2]. The majority of resins consist mainly of compounds based on diterpenes, C20H32.
The most common type of amber contains members of a diterpenoid family known as labdanoids. These components readily polymerize to form macromolecular compounds.
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Excerpted with permission, Chemical & Engineering News
Copyright © 2007 American Chemical Society