The 4C's

CARAT
A diamond's size is measured in carat weight, and each carat is equal to 100 points. A .75 carat diamond is the same as a 75 point diamond or a 3/4 carat stone.

While larger diamonds are highly prized, diamonds of equal size may vary widely in value and brilliance, depending on their qualities of clarity, cut, and color.

CLARITY
The greater a diamond's clarity, the more brilliant, valuable and rare it is. Virtually all natural diamonds contain identifying characteristics, yet many are invisible to the naked eye. Under the scrutiny of a 10x-magnifying loupe or microscope, natural phenomena, called inclusions, may be seen. These are nature's birthmarks, and they may look like tiny crystals, clouds, or feathers.
Diamonds categorized as internally flawless reveal no such inclusions. Flawless stones are at the peak of Diamond Quality and are treasured for their rarity and beauty. Diamonds with very, very small inclusions are graded as VVS1 or VVS2. The larger the inclusion, the lower the grade and the less rare the diamond. Inclusions that can be seen with the naked eye are graded I1, I2 or I3.
The number, color, type, size and position of surface and internal birthmarks affect a diamond's value. Major inclusions can interfere with the path of light that travels through a diamond, diminishing its brilliance and sparkle and therefore its value.

COLOR
The More Pure the Color in a Diamond, the More Rare. Diamonds are graded by color, starting at D and continuing through Z. Truly colorless stones, graded D, are treasured for their rarity and value. While many diamonds appear colorless, they may actually have subtle yellow or brown tones. Although still beautiful, they will be less rare and therefore less valuable. "Fancy" diamonds, in well defined colors that include red, pink, blue, green and canary yellow are highly prized and particularly rare.

CUT
The Better Cut a Diamond, the More Brilliant. A well cut or faceted diamond, regardless of its shape, scintillates with fire and light, offering the greatest brilliance and value.
While nature determines a diamond's clarity, carat weight and color, the hand of a master craftsman is necessary to release its fire, sparkle and beauty. When a diamond is cut to good proportions, light will reflect from one mirror-like facet to another and disperse through the top of the stone, resulting in a display of brilliance and fire. Diamonds that are cut too deep or too shallow lose light that spills through the side or bottom. As a result, poorly cut stones will be less brilliant and beautiful and certainly less valuable than well cut diamonds