Diamond Glossary

Brightness
The appearance, or extent, of internal and external reflections of "white" light seen in a polished diamond when it is viewed face-up. 

Craftsmanship
A description of the care that went into the crafting of a polished diamond, as seen in the finish (polish and symmetry) of the diamond. 

Design
Decisions made during the fashioning process that determine a diamond's physical shape, as seen in a diamond's proportions, weight ratio, and durability. 

Durability
The characteristics of a polished diamond that accounts for the risk of damage inherent in its proportions (i.e., the risk of chipping in diamonds with extremely thin girdles). 

Face-Up Appearance
The sum appearance (brightness, fire, scintillation) of a polished diamond when it is viewed in the table-up position. This appearance includes what is seen when the diamond is "rocked" or "tilted."

Fire
The appearance, or extent, of spots of light dispersed into spectral colors seen in a polished diamond when it is viewed face-up. 

Metric
A calculated numerical result obtained through computer modeling; for the GIA diamond cut research project, metrics were calculated for brightness and fire for both hypothetical and actual diamonds. 

Overall Cut Appearance and Quality 
A description of a polished diamond that includes the face-up appearance, design, and craftsmanship of that diamond. 

Scintillation
1. Sparkle: The appearance, or extent, of spots of light seen in a polished diamond when it is viewed face-up that flash as the diamond, observer, or light source moves. 
2. Pattern: The relative size, arrangement, and contrast of bright and dark areas that result from the internal and external reflections seen in a polished diamond when it is viewed face-up while that diamond is still or moving. 

Weight Ratio
A description of a diamond's overall weight in relation to its diameter.