If this is the start of a Zodiac series, I think you should go with the signs colors, which for Gemini would be yellow or red, depending on the cusp. Yellow is the most commonly accepted, which would fit with the birthstone, Topaz. Again, depending on the cusp or west to east. But Yellow and Topaz are the most widely accepted.
Now for a small fee I would be happy to do a past life regression for you. However, I have to draw the line at reading the bumps on your head. I don't think that it would be good for either of us. 
