Art Deco black opal and diamond ring, circa 1935.

This ring is in excellent condition.

Black opals were formed approximately 60 million years ago when silica rich water was carried into cracks and voids within the earth. As the water evaporated, it left behind a silica deposit, which has created the beautiful opals that we know today. The colours visible in the play-of-colour of an opal depends on the structure of the gem, and depending on which angle the light hits the opal, it is diffracted differently due to the complexity of the structure, creating this fleeting, almost mystical, effect. Black opals are considered to be the rarest and most beautiful of the opals, and the play-of-colour contrasts beautifully against a dark body colour.