Hue is the basic color of a gem, such as red, blue or green. A second color can modify it, as in purplish red.
In more detail
Hue can decide the variety. Red must be the dominant hue before GIA calls a stone ruby. In ruby, pure red to slightly purplish red is valued most.
On a grading report
Colored stone reports state the color in words, such as 'purplish red'.
Related terms
- Tone: Tone is how light or dark a gem's color is, from very light to very dark.
- Saturation: Saturation is the strength or purity of a gem's color, from grayish or brownish to vivid.
- Gem variety: A variety is a subdivision of a gem species, usually by color. Ruby and sapphire are varieties of corundum, and emerald is a variety of beryl.
- Pink sapphire: Pink sapphire is corundum whose color is pink rather than red. Chromium causes both its pink and the red of ruby.
- Trade color term: A trade color term is a market name for a fine color, such as pigeon's blood, royal blue or cornflower. It is not a gemological standard.