Basic Info on Diamonds

  • Home
  • /
  • Basic Info on Diamonds

What is a diamond?
A diamond is a crystal made up entirely of carbon atoms that are arranged in an isometric, or cubic, matrix. A cubic crystal arrangement is one in which the crystal essentially expands outward at the same rate in all directions during its initial growth; the ideal result, when the crystal forms without any interference, is a pure and perfectly formed octahedral shape.

However, most diamond crystals encounter varying heat or pressure, other elements, or even other diamond crystals during their growth, and this can alter their form somewhat. The resulting form and characteristics of the crystal, once it emerges from the earth, help to determine what shape, color and clarity the polished gem will have.

The combination of diamond's molecular composition and its crystal structure is what makes it so unique and gives it all the qualities that we think of when we think of a diamond.

Consider this: The graphite that you commonly find in pencils is also made of pure carbon, but because the carbon atoms are arranged differently, the result is a soft gray-black substance that is very unlike hard, colorless diamond. And iron pyrite (known more commonly as "fool's gold") grows in an isometric arrangement, but because it is not made of pure carbon, it also lacks the spectacular qualities of diamond.

The unique characteristics of diamond go far beyond what you can see with your eye. In addition to their superior brilliance and dispersion, diamonds are the hardest natural substance on earth.

Diamond rates a 10 on the Mohs scale of hardness, which means that it is extremely resistant to scratches; it is several times harder than the next-hardest substance, corundum, which is more commonly known as ruby and sapphire.

Diamonds are also very tough, meaning that they do not easily break, chip or crack. And even more interestingly, they are extremely resistant to heat and chemicals: it would take a temperature of at least 720° Celsius in air, or 850° Celsius in a vacuum, to burn a diamond; and sulphuric and hydrochloric acids, which are capable of completely dissolving the skin and bones of a person, have no effect at all on diamonds (in fact, these acids are actually used to clean the oil and dust off polished diamonds after they have been cut).

Where do diamonds come from?

Diamonds are made up of pure carbon atoms that exist deep in the ground, exposed to intense heat and pressure over billions of years. Over time, this pressure builds up and forces the diamonds and rocks up toward the surface in a volcanic-like explosion. The explosion creates a very deep, wide hole called a "pipe" into which most of the diamonds settle; these deposits of diamonds are known as primary deposits. Other diamonds are washed away by water or erosion, and often settle into the coastal waters of nearby bodies of water; these are alluvial deposits. These deposits occur in many places around the globe; however, the largest commercial deposits exist in Angola , Australia , Botswana , Namibia , South Africa , Russia and Zaire , which produce 80% of the world's diamonds.

Walking through the aisle of a jewelry store, you may not think diamonds are especially rare. But consider this: 250 tons (500,000 pounds) of ore must be mined and processed to produce just one carat of rough diamond. Since a rough diamond typically loses 40% to 60% of its weight when cut, that means that all these efforts are necessary to produce just one of the .50 carat polished diamonds you find in the store's display counters. When you also consider the fact that only about one quarter of all rough diamonds are actually suitable for gem cutting, you can begin to appreciate the rarity and uniqueness of each diamond.

A quick, fun fact: The first diamond deposits were brought to the surface of the earth approximately 2.5 billion years ago. The most recent deposits are roughly 50 million years old. Your diamond is a truly unique piece of history.

How is a diamond cut?

A newly mined rough diamond looks more like a piece of glass washed up on the beach than like the polished gems sold in jewelry stores. Bringing out their beauty requires the skill and art of a trained diamond cutter.

While incredibly precise, computerized machinery is now used in some parts of the cutting process for some diamonds, most of the work is still performed by hand using exacting and meticulous techniques passed down over the generations.

As a first step, cleaving or sawing is often used to separate the original rough into smaller, more workable pieces that will each eventually become an individual polished gem. Next, bruting grinds away the edges, providing the outline shape (for example, heart, oval or round) for the gem. Faceting is then done in two steps: during blocking, the table, culet, bezel and pavilion main facets are cut; afterward, the star, upper girdle and lower girdle facets are added.

Once the fully faceted diamond has been inspected and improved, it is boiled in hydrochloric and sulfuric acids to remove dust and oil. The diamond is then considered a finished, polished gem.