Crushed Opal. Our Crushed Opal is a synthetic lab-made or cultured opal. Natural opal can crack and craze over time, but the polymers in the cultured opal make it much more stable, workable, and economical than natural opal. The magical brilliance, stunning color, and unsurpassed vibrancy make this crushed opal the perfect choice for making rings as well as all types of inlay work.