Diamond
A diamond is the hardest known natural substance. It is crystallized carbon. Diamonds are mined in their rough form and then cut and polished to reveal their brilliance.

Diamond Grading Reports
There are many recognized gemological laboratories that can grade your diamond for a fee.

Dispersion
When light enters a diamond it reflects off the facets and the angles cut into the stone. This distribution of light is known as dispersion, or the display of the spectral colors.

Emerald shape
A rectangular or square-shaped cut-cornered diamond.

Facets
These are tiny surfaces polished onto a rough diamond that give a finished diamond its shape. The way light interacts with these facets affects a diamond's brilliance and sparkle.

Fancy shapes
Any diamond shape other than round - e.g. marquise, square, emerald, oval, heart and pear.

Feather
A feather is a type of inclusion or flaw within a diamond. It is described often as a small crack, fissure or gletz.

Finish
The word finish is used to describe the exterior of the diamond. If a diamond is well polished, it has a very good finish.

Fire
Often a term used instead of "dispersion," it is the variety and intensity of rainbow colors seen when light is reflected from a diamond.

Flat-top setting
Like the Gypsy setting, this setting has a band that is one continuous piece that gets thicker at the top. A flat-top setting grows broader at the top so that a faceted stone can be inserted into the ring at the broadest part. The stone is held in place by metal chips attached at the stone's girdle.

Fluorescence
When exposed to ultraviolet light, a diamond may exhibit a more whitish, yellowish or bluish tint, which may imply that the diamond has a property called fluorescence. The untrained eye can rarely see the effects of fluorescence. Diamond grading reports often state whether a diamond has fluorescent properties. Fluorescence is not considered a grading factor, only a characteristic of that particular diamond.

Girdle
The girdle is the outermost edge of the diamond between the crown and the pavilion.

Growth or grain lines
These can be considered internal flaws, and can often be seen only by rotating the diamond very slowly. They can appear and disappear almost instantaneously. They appear as small lines or planes within the diamond.