What's in a diamond?

A lot has been said about diamonds. They are forever, they are a girl's best friend - take your pick. But how much do you know about the gem that has captured the hearts and attention of people around the world? Here's some basic information about the diamond that's glittering from your engagement ring or floating on your necklace:

Mineral

Diamonds are made of pure carbon. Diamond is the hardest naturally occurring substance on the planet, earning a 10 on the Mohs scale. Because of their strength and durability, diamonds are used in a number of industrial facets. For example, diamonds have been fixed on drills used to cut stones in quarries. Carbon hardens into diamonds under extreme heat and pressure in the earth's mantle. Interestingly, carbon is also the mineral used in graphite pencils. Graphite is notoriously soft.

This beautiful gem can be found in three types of mineral deposits: alluvial gravels, glacial tills and kimberlite pipes. Magma pushes up into the earth's crust to form kimberlite pipes. Diamonds and other minerals are shot from the mantle through the pipes up to the surface. The pipes may be as young as 100 million years old, while diamonds can be 1 to 3 billion years old.

Color

Diamonds come in a variety of colors. White diamonds are transparent, though low-valued gems appear yellowish. White varieties are given the highest value when they have the least amount of color. Fancy colored diamonds can be just about any hue imaginable. Famous gems have been pink, yellow and orange. Several massive pink diamonds have recently sold at auctions for large sums of money. All the colors occur naturally.

Some diamonds have a property called fluorescence, which causes them to glow under ultraviolet light. They appear translucent in natural light. While fluorescence can produce a shine in several colors, blue is the most common. These gems often sell for less than diamonds without the feature because some argue that fluorescence adds some visible color to an otherwise white diamond.

Cut

Diamond cut is arguably one of the most important features of the gem. It takes expert hands to craft a diamond with perfect symmetry. This gem can be cut into any of the most popular shapes because its harness makes it durable. The round brilliant cut is among the most popular diamond cut shapes.

Facts

A diamond mine will produce one part diamond to one million parts rock, making the gem truly one in a million.

Diamond is the birthstone for April, and the gem for 60th and 75th wedding anniversaries.