Real or Fake? How to Test Your Opal's Authenticity Identifying whether an opal is real or not involves several steps or key tests, so here’s a detailed identification guide from which anyone can recognize whether the opal is real or fake. In this guide, the very first test that is involved is its visual representation. In this step, we will check two visual representations. The very first is a play of color as real opals display an extraordinary play of variety, known as opalescence, which is brought about by the diffraction of light inside the micro-structure of the stone. This play of variety seems to move and change as the stone is moved and seen from various points. Fake opals can likewise show the play of variety. However, it frequently shows up too great or customary, lacking the natural randomness of real opals.