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RUBY, RUBY - How did you get so RED!
Painting the Ruby
July 04, 2017 | Author: Sharon Elaine Thompson
If you know your Alice (as in Wonderland), you know the Red Queen’s demand that her minions paint all the white roses red. Same thing happens in the gem world. Many gemstones are “white” or colorless in their pure state. Through the eons the crystals spend growing in the earth, they often pick up trace elements which “paint” them the famous colors they are known for. (Gemstone color can be caused and affected by a great many things, but let’s stick with trace elements here for simplicity.) A perfect example of this is ruby, birthstone of July.
The reason is this: White light is made up of all the colors of the rainbow. When it strikes or passes into an object, like a gemstone, light breaks up into all its component colors. The gemstone absorbs, reflects, or transmits those different color wavelengths depending on the particular atomic properties of the gem material and any trace elements. Rubies (specifically the chromium therein) absorb everything but the red wavelengths. As a result, red is the color we see when we look at a ruby.
An interesting aspect of the red in rubies that I would guess has to do with the chromium: If they’re heated with a torch — during repair at the bench, for instance — they’ll go green. The first time I saw this, a customer’s ring was under repair. I think I stopped talking in the middle of a sentence. The jeweler glanced at me and said, “Don’t worry. They’ll turn red again when they cool.” They did.
This color explanation is pretty simplified. If you’d like to learn more, or simply want help sleeping on difficult nights, you can check out your back issues of Lapidary Journal; (March 1992, specifically) for my article “Painting the Ruby Red.” Pleasant dreams!
