Meet Mia,

A Vintage Luciano Bortone Black Boulder Opal & Diamond Ring in 18k Yellow Gold

This exceptional vintage piece features vibrant greens that roll and flash across the gemmy blue body of the black boulder opal, sourced from Queensland, Australia. Set in solid, well-crafted 18k yellow gold with four round brilliant diamonds totaling approximately one-tenth of a carat, the stone shows a true clean face—a term used for boulder opals that display no ironstone inclusions when viewed from above. Its N4 body tone places it firmly in black opal territory, giving the color play uncommon depth and intensity for a stone of this size.

The ring is petite by design. The round opal measures 6.6 millimeters in diameter—no larger than a pencil eraser—and the full bezel brings the top width to roughly 8.2 millimeters, or about one-third of an inch. Despite its compact footprint, the piece has surprising heft and presence thanks to its build quality and its square Euro shank, a signature of Luciano Bortone’s work that helps prevent the ring from spinning on the finger. The unisex profile allows it to be worn by men or women; for male wearers, smaller hands or a pinky finger tend to complement the proportions best. For women, the ring’s low profile makes it easy to wear daily and a fitting choice for someone seeking a practical, understated engagement ring.

Crafted and signed in the 1990s by Laguna Beach opal jeweler Luciano Bortone, the ring came to us from a Southern California estate. It arrived in well-loved condition, and our team invested considerable time restoring it with care. The structure, bezel, and channels remain strong. Some faint evidence of past wear can still be found in certain areas of the gold when viewed closely, and the opal—now repolished—may show subtle polish lines under specific lighting at close inspection. These nuances are consistent with its age and craftsmanship and are not visible during normal wear.

What remains is a finely made, highly wearable boulder opal ring—compact, substantial, beautifully executed, and unmistakably the work of a seasoned artist. It carries both the quality of its maker and the quiet confidence of jewelry built to endure.

More Information

The Center Stone: Natural Black Boulder Opal, solid

• origin: Queensland, Australia
• brightness of color play: B4 of 5
• body tone: N4
• shape: round flat-domed cabochon cut
• stone diameter (millimeters): 6.62mm
• stone diameter (inches): 0.25"
• play of color description: green-blue only

The Accent Stones: Diamond, natural

• stone count: 4
• approximate total carat weight: 0.10ct
• cut: Standard Round Brilliant Cuts
• average clarity grade: VS2
• average color grade: F-G-H

The Setting: Low-Profile Bezel Set Ring with European-Style Shank, signed

• metal: 18k yellow gold, solid
• top of ring width: 8.22mm (0.33")
• ring height from finger: 3.96mm (0.2")
• bottom of shank width: 5.13mm (0.2")
• ring weight: 8.34 grams
• approximate default ring size: 6.25 US