You cannot go wrong with a tourmaline. While at a rock and mineral show when I was a kid an old toothless overall-clad rock hound told me that the Egyptians believed that tourmaline came from the sun and passed through a rainbow on its way into the earth and that's how it got all of its colors. I remember listening to that old guy and being equal parts entranced by his tourmaline specimens and the story I had just been told.
No matter what color you like, there's a tourmaline for you. Faceted or cabochon, these pretty stones positively sing. Here's my ode to that rainbow.