Labradorite is an amazing stone that can appear dark at first, until you move it and the stone comes alive with colors flashing within. The effect is similar in appearance to opal fire. It is called chatoyancy, which is a fancy way of saying that the color 'flashes' or 'rolls' across the stone, like cat's-eye but far more vibrantly. It is a natural stone, and the effect is caused by refractive layers within the stone. It cannot be simulated or dyed to look that way! You can see the effect here (not contractual movie) : [link]