1. Facet: any of the flat "sides" of the gem.
2. Table: On a brilliant-cut stone...the top octagonal facet.
3. Girdle: The typically frosty white ring at the widest part.
4. Cutlet: The bottom point (actually facet) on a brilliant-cut stone.
5. Pavilion: The portion of the stone below the girdle.
6. Crown: The portion of the stone above the girdle.
7. Diameter: Width of the gem as measured thru the girdle.
8. Fire: The quality of the gem that breaks reflected light into a colorful array.
9. Depth: Height of Gemstone from Cutlet to Table.
10. Brilliance: The quality of the gem that reflects light without changing it (also called sparkle).
11. Fluorescence: The characteristic of some gems is to fluoresce certain colors under some light.
12. Natural: Usually found on the girdle. A small section was on the side of the raw gem. It appears as a slightly rough flat spot on the girdle.
13. Feather: A “crack” is a gem, that appears as a white feather within the stone.