Diamond is a crystalline form (or allotrope) of carbon, whose hardness and high dispersion of light makes it useful for industrial applications and jewellry. Other allotropes of carbon include graphite, fullerene and ceraphite — but diamonds are specifically renowned as a mineral with superlative physical qualities. They make excellent abrasives because they can only be scratched by other diamonds, which also means they hold a polish extremely well and retain luster. About 130 million carats (26,000 kg) are mined annually, with a total value of nearly 9 billion US$.

Cut

The cut of a diamond has the most effect on its sparkle, or brilliance. Even if the diamond has perfect color and clarity, a poor cut can make a diamond look dull. Blue Nile carries only the highest grades of diamond cut, for the most sparkle. Learn how to choose the right diamond cut with the most brilliance for your budget.

Color

Diamonds with very little color are the most highly valued and are priced accordingly. A little color can diminish a diamond's brilliance. To help you choose the most brilliant diamond, We offers diamonds with the highest grades of color. Learn how to choose a diamond with no color noticeable to the unaided eye.

Clarity

Diamonds with few flaws, or inclusions, are very rare and highly valued. Clarity is graded based on the number, location, size, and type of the inclusions found in a diamond. Blue Nile has some of the clearest diamonds available. Learn how to choose the right grade of clarity for your diamond.

Carat Weight

The weight of a diamond is measured in carats. Since larger diamonds are more rare than smaller diamonds, diamond value tends to rise exponentially with carat weight. Read more about carat weight and learn how to balance diamond quality with the size of your diamond.