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.
In more detail
Varieties of one species share their optical and physical properties. Color belongs to the variety, so ruby and blue sapphire absorb light differently. The line between two varieties, such as ruby and pink sapphire, is a color judgment.
On a grading report
The variety name is usually the name the buyer knows: ruby, sapphire, emerald, amethyst.
Related terms
- Gem species: A gem species is a mineral with one chemical composition and one crystal structure, such as corundum, beryl or quartz.
- Ruby: Ruby is the red variety of the mineral corundum. Chromium causes its red color.
- Pink sapphire: Pink sapphire is corundum whose color is pink rather than red. Chromium causes both its pink and the red of ruby.
- Green beryl: Green beryl is a green beryl that does not qualify as emerald. Its color is too weak, or iron rather than chromium or vanadium mainly causes it.
- Hue: Hue is the basic color of a gem, such as red, blue or green. A second color can modify it, as in purplish red.