Friday, April 17, 2009

History of Diamonds

Diamonds are the hardest substance known on Earth. They make sparkling jewelry as well as saw blades that can cut through pretty much anything. Diamonds form deep within the Earth's mantle layer from the element carbon that is under huge amounts of pressure from the load of rocks above.

Recently, scientists studying diamonds have found the ages of thousands of diamonds from Southern Africa, where most diamonds are found. They discovered that there were only three times during Earth’s history when diamonds were made and that Earth no longer makes diamonds like it used to. “Something was different then. Perhaps the planet was hotter on the inside, or the composition of the rocks was subtly different. Whatever it was it has changed now,” stated Steve Shirey, one of the project scientists.

The oldest diamonds were made 3.3 billion years ago when Earth was rather young. The second time diamonds were made was 2.9 billion years ago. The scientists think that these diamonds were probably formed from rocks that lay at the bottom of a shallow sea. The carbon that made these diamonds probably came from ancient sea life. The youngest diamonds on Earth are 1.2 billion years old although a few smaller diamonds are about 100 million years old.

Some people like diamonds because they are pretty, rare, or expensive but Dr. Steve Shirey has a different view. “I think of diamonds,” he said, “as being tiny time capsules that encase a little piece of rock protecting it for billions of years and providing us with a unique window on ancient times.”

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