HOW TO CHOOSE

Black opals are polished to minimize weight loss while showing as beautiful a surface as possible. Consequently, each piece is unique in its shape and in the way it exhibits color, making each one-of-a-kind. It is wise to choose a gem- or jewelry-quality stone of 1 to 3 carats.

When considering production costs and the quality of design, it is probably best to purchase a finished ring or earrings at a reputable store. A loose black opal can be purchased overseas and brought home, but opals have low hardness and contain water, so remember that accidents may occur during manufacturing.

The value of a three- carat-size black opal of jewelry quality is approximately US $3,000 for the stone alone (2004).