Vintage 1990s Boulder Opal and Sapphire Convertible Pendant Brooch in 14kt Yellow Gold

ARTICLE: Convertible pendant and brooch, 14kt yellow gold, centering one natural Australian boulder opal with sapphire accents. American, circa 1990s.

MOUNTING: Fabricated in 14kt yellow gold with sculptural ribbon and scroll work rising over the upper edge of the stone. Center stone bezel set. Fitted with two loops to the reverse through which a chain may be passed, together with a straight pin and swivel safety catch permitting the piece to be worn as a brooch.

CENTER STONE: One freeform natural boulder opal measuring approximately 1.25 by 0.75 inches. Play of color displays iridescent blue and purple distributed across a dark ironstone matrix.

ACCENT STONES: Three round natural sapphires, each measuring 2.60 mm: one blue, one purple, and one green.

CONDITION: Examined under magnification and found to be in excellent condition. All stones present and secure at the time of examination. Bezel tight to the opal with no separation. Pin straight, and the swivel catch engages and holds correctly.

NOTE ON THE STONE: Boulder opal is a solid natural stone. The dark ironstone visible behind and through the color is the host rock in which the opal formed, cut and retained as part of the gem. It is not a doublet or a triplet, and nothing here has been assembled or backed. Because that ironstone gives the opal a natural structural backing, boulder opal is among the more durable of the precious opals and is materially less prone to crazing than sedimentary opal from the South Australian fields. The material is found almost exclusively in western Queensland, Australia.

REMARKS: Freeform boulder opal is cut to follow the seam rather than to a calibrated shape, so every stone dictates its own mounting and no two pieces are alike. The goldsmith here has answered that by building an asymmetric scrolled crown over the top of the stone rather than imposing a symmetrical frame on it, and by setting the three sapphires in different colors rather than a matched trio. The convertible fitting is a practical piece of design: two chain loops and a proper swivel catch pin, both executed well, rather than one function added as an afterthought.

CARE: Avoid ultrasonic and steam cleaning, prolonged direct sunlight, and abrupt changes in temperature. Clean with warm water, mild soap, and a soft brush.

Measurements and descriptions stated are approximate and determined while the stones are mounted, in accordance with standard practice for jewelry examined in the setting.