Glossary: I-N

IGI International Gemological Institute. Organization which makes diamond certificates.
Inclusion Internal characteristics/flaws present in diamonds. Such as: pinpoints
Internal graining Visible growth lines within the diamond.
Irridation of diamonds Used for color enhancements. Can cause radioactive stones.
Kimberlite Volcanic rock in which diamonds can be found.
Knot Diamond crystal inside the diamond. Cannot be seen unless it touches the surface of the mother stone.
Laser drill hole Tunnel created by a laser from to surface of the stone towards an inclusion.
Laser Inscription Diamonds can be inscribed (usually on the girdle), often done for identification purposes.
Length-to-width ratio Calculation of how much longer a fancy shape is than it is wide.
Luster Amount of reflected and refracted light from the surface of the diamond.
Make Includes proportions, symmetry, and polish of a gemstone.
Make Proportions & finish of a polished diamond. Also known as the cut.
Marquise Diamond shape with pointed ends and an elliptical girdle outline.
Melee Round faceted diamonds smaller than 0.20 carats.
Mohs scale Scale of hardness, created by Friedrich Mohs; in which diamond is expressed to have a hardness of 10 and thus bein the hardest natural material.
Natural Original rough portion, left by the cutter when polishing the diamond. Usually found near the culet or girdle.
Natural Girdle Unpolished girdle
Needle Internal characteristic. Long and thin inclusion.
Nick External characteristic describable as a chip/cavity on the diamond girdle.