The word "diamond" comes from the ancient Greek "adamas," meaning unconquerable.

"Carat," the measure of diamond weight is derived from the Greek "keration," the name for the uniform in weight carob seed.

Cut, color, clarity, and carat are the "4Cs" that guide a jeweler in determining a diamond's value.

"Clarity" refers to a diamond's freedom from internal inclusions such as internal cracks or tiny crystals. A diamond may be termed "flawless" if a trained eye can detect no inclusions under 10-power magnification.

"Cut" refers to the way a diamond is cut and polished, the proportion of the diamond that dictates the maximum amount of light the diamond will refract and reflect, and the diamond's facets.

The term "fancy" diamond means pear, oval, or emerald cut stones.

Red is the very rarest color for a diamond.

Marilyn Monroe's famed comment as the character Lorelei Lee, "Diamonds are a girl's best friend," is a classic. But Mark Twain in "Puddin' Head Wilson's Calendar" said, "It is better to have old second-hand diamonds than none at all."

A carat is divided into 100 points.

The "old miner" refers to a diamond cut that is round but has many fewer facets than the modern brilliant cut.

The color deemed ideal for a gem quality diamond is colorless.

The Hope Diamond is a rare and famous example of a diamond with a deep blue body color.

Diamond Jim Brady, whose diamond studded accessories caused quite a stir, showered ladyfriend Lillian Russell with extravagant diamond gifts among which was a diamond bracelet with her name in red diamonds.

Industrial diamonds, which are used in precision machinery because they are the hardest substance known, differ from gem diamonds because they are of inferior color and quality.

The man who first discovered how best to release the diamond's fiery brilliance from the unprepossessing rough gem was Vincenti Peruzzi, a Venetian lapidary who lived in the 17th century.