Dispersion - the spreading and separating of white light into its spectral colors as it passes through a gemstone. Another name for dispersion commonly used is fire.
Durability - the combined characteristics of hardness, toughness and stability of gemstones.
Dwt
- abbreviation for pennyweight. A unit of mass which is the same as 24 grains, 1/240th of a troy pound or approximately 1.555 grams.