Gemstone Characteristics

Carat

• Carat is a measurement of weight used to determine the value of a gemstone. It can be misinterpreted as representing a stone's size, but what carat really measures is a gemstone's density. One carat equals 0.2 grams. This is why one carat of one stone may not be the same size as one carat of another stone. Denser, heavier stones are classified as one carat at a much smaller size than a lighter stone.

Color

• Gemstones come in all different colors, but their value is determined by the richness of that color. This is known as the intensity of the color. A dark-blue sapphire, for example, is worth more than a pale one. Some gems are also expected to maintain some transparency. Rubies, emeralds and sapphires are examples of stones that are more valuable when light can pass through them. This is one property that makes a diamond so valuable, despite its lack of color. Because it refracts light, it appears to sparkle. Other gemstones, such as opal, are opaque because their chemical makeup does not allow for transparency.

Clarity

• Some gemstones grow with inclusions, or mineral and crystal deposits. In some cases, inclusions can be eliminated when a stone is cut. In others, however, inclusions are left intact. This is because there is no universal way to measure the impact of inclusions on the worth of a stone. In general, however, stones with fewer inclusions are worth more money because of their transparency and ability to reflect light.

Cut

• Many gemstones are worth very little before they are cut. Rough sapphire, emerald and ruby, for example are dull in color and lack transparency. The skill of a cutter often determines the worth of a stone. A cutter will attempt to include the richest color and clarity in a cut. Each cut is made with the individual characteristics and qualities of each stone in mind.