This picture shows the Hope Diamond, a blue diamond, surrounded by other white diamonds. Click on image for full size (32K JPG)

Diamonds are the hardest substance known on Earth and they make sparkling jewelry as well as saw blades that can cut through pretty much anything. They form deep within the Earth's mantle layer (about 200 km deep) when atoms of the element carbon arrange themselves into a lattice under huge amounts of pressure from the load of rocks above.

Recently, geologists studying diamonds have identified the ages of thousands of diamonds from Southern Africa, where the mineral is most abundant. Their research found that there were only three times in 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, of the Carnegie Institution in Washington, D.C., one of the project researchers.

The oldest diamonds were made 3.3 billion years ago when Earth was relatively young. The second time diamonds formed was 2.9 billion years ago. Small bits of rock within those diamonds, called impurities, indicate that they probably formed from rocks laid down in a shallow sea suggesting that the carbon that made the diamonds probably came from the remains of 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 perspective. “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.”

This picture shows the Hope Diamond, a blue diamond, surrounded by other white diamonds. Click on image for full size (32K JPG)

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.”

This picture shows the Hope Diamond, a blue diamond, surrounded by other white diamonds. Click on image for full size (32K JPG)

Diamonds are the hardest things on Earth. They make sparkling jewelry and saw blades that can cut through anything. Diamonds form deep within the Earth's mantle layer from stuff called carbon that is under pressure from the heavy rocks above it.

Scientists have found that all diamonds are really old! 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.

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 youngest diamonds on Earth are still very old. They are 1.2 billion years old but a few smaller diamonds are only about 100 million years old.