Source: Nature: "Diamonds"
Major corporate support for the Nature collection was provided by Canon U.S.A. and SC Johnson. Additional support was provided by the Corporation for Public Broadcasting and the nation’s public television stations.
National K -12 Subject:
Lesson Plans Using this Resource:
A diamond with inclusions may lack material value, but it holds a wealth of information for geologists studying the composition of the Earth. A diamond's inclusion is a pristine specimen of Earth's mantle from which geologists are able to extract data about Earth's geological structure. Learn about diamond inclusions in this video segment from Nature.
Download and ShareTranscript (Document)
Diamonds are minerals that are valued for their durability, beauty, and rarity. They form deep in the earth under conditions of extreme heat and pressure, and are brought to the surface of the earth by the forces of volcanism and weathering. Generally, diamonds - and the rocks they’re found in - are very old. Studying diamonds, therefore, can help scientists reconstruct the processes that were central to the formation of the earth itself.
The physical properties of a diamond are determined more by the crystal structure of the diamond than by its composition - consider that diamond and graphite, despite their vastly different physical properties, are both composed of pure carbon. Every mineral is characterized a particular type of crystalline structure that is largely responsible for its physical properties.
Inside a diamond, the bonds between atoms of carbon are the strongest known. This makes diamonds not only the world’s hardest substance, but four times harder than the next hardest material.
Like amber encasing an insect, diamonds sometimes capture bits of surrounding minerals. Geologists call these fragments “inclusions.”
LT: The inclusion occurs inside the diamond. Everything around the diamond has changed its integrity, it changed everything about it, its chemistry, but the little inclusion inside has remained pristine and virginal to this day, and this is the little piece of material that we’re looking for.
Using high-resolution x-ray tomography, a technique similar to a CAT-scan, Taylor and his team create a three-dimensional map of the volcanic rock, the diamonds, and the inclusions inside. They may contain garnets, or sulfide minerals, and other substances that can only be formed at hundreds of thousands of atmospheres. Analyzing these minerals reveals one of diamond’s astonishing secrets.
LT: As best we can tell, the inclusions that are inside a diamond date the diamond at being approximately somewhere between two and three billion years old.
At three billion years old, diamonds are among the earth’s oldest creations. They are time capsules, carrying information and mystery. To Taylor, a diamond’s true value is in what it can tell us about the distant past and the inner workings of the planet.
Loading Standards
Background Essay
Print Background Essay