Four distinct factors make a diamond trult spectacular. Collectively, these "Four Cs" determine the value of a diamond.
"Carat", This word refers to the measurement of a diamonds weight. A carat is equal to 200 milligrams and there are 142 carats to an ounce. Carats are further subdivided into points, containing 100 points each, A half-carat diamond is often referred to as a 50-point stone. Because they are so rare, large diamonds generally have a greater value per carat.
"Color", While diamonds are available in virtually every color of the spectrum, the most popular are colorless. However, truly colorless, icy-white diamonds are extremely rare and therefore the most costly. Stones are graded by their color, depending upon how far they deviate from the purest white. Colorless stones are graded by their color, depending upon how far they deviate from the purest white. Colorless stones are graded D. Color grading continues down through the alphabet (E,F,G, etc), with each letter designating a yellower tint. The best way to see the true color of a diamond is by looking at it against a white surface. Although the great majority of diamonds come in shades of white, the gems also come in a range of breathtaking colors. Known as "fancies", these colorful diamonds are valued for their depth of color in much the same way that white diamonds are valued for their lack of color.
"Clarity", A diamond's clarity is impacted by external irregularities and internal imperfections created by nature. Imperfections such as spots or lines are called "inclusions". While these make each stone unique, diamonds with fewer inclusions have a greater value. This si because inclusions can hinder the passage of light through a stone, muting its sparkle and decreasing its value. According to the Gemological Institute of America's quality analyses system, clarity is graded on a scale ranging from flawless (FL or IF) to imperfect(I). To achieve a grade of "flawless", a diamond must have absolutely no inclusions visible to a trained eye under a 10x magnification in good light.
"Cut", Each diamond is cut according to a very precise mathematical formula. A poorly cut diamond will actually lose light and appear dull. The round brilliant is the most common cut, containing 58 facets (small, flat, polished planes designed to maximize the light reflected back to the observer). The widest circumference of a diamond is known as the "girdle", above the girdle of a brilliant cut diamond are 32 facets; plus the largest facet, or table, at the very top. Below the girdle are 24 facets plus the culet, or point. A diamond's cut also describes its shape. Other popular cuts include pear, emerald, marquis, oval and square.