traditional fire opals and opals that have rarer patterns that look like peacock feathers, harlequin squares or stars. One wall is lined with jars, filled with gray, broken rocks. The rocks are ...

By the time the second case of beer was empty, Tremonti owned the 16-carat harlequin opal, a fluke of nature that presents a checkerboard pattern, with each square emanating a different hue.