4-Piece Job Lot of Premium "Sterling Opal" Loose Cabochons
Total Estimated Weight: Approx. 9.08 Carats
Lot of four premium, lab-grown "Sterling Opal" cabochons. Unlike the more common "Monarch" opals on the market, these stones feature a perfectly clean, non-matrix background with no black cracked lines. Instead, they showcase a spectacular, uniform pinfire flash of vibrant green and turquoise sparkles (with some reds and oranges) across a clean, milky-white base.
This set is perfectly matched in colour, flash intensity, and pattern, making it an incredible bundle for UK silversmiths, wire-wrappers, jewellery makers looking to create a matching collection (such as a ring, pendant, and accent pieces).
Individual Stone Dimensions & Details:
- 1x Marquise Cabochon: 16.0mm x 8.0mm x 3.9mm (Approx. 2.85 ct)
- 1x Oval Cabochon: 13.9mm x 9.9mm x 3.7mm (Approx. 2.90 ct)
- 1x Oval Cabochon: 13.9mm x 9.9mm x 3.9mm (Approx. 3.06 ct) - Near perfect pair with the oval above!
- 1x Small Round Accent Cabochon: 5.3mm diameter x 1.7mm deep (Approx. 0.27 ct)
Sterling Opal is technically classified as a polymer-impregnated synthetic opal.
- Silica Base (approx. 80%): True lab-grown microscopic silica spheres are grown over many months to mimic the exact structural makeup of natural precious opal. This is why they flash real "Bragg diffraction" structural fire colours under the light, rather than using fake dyes or glitter.
- Polymer Resin (approx. 20%): The porous lab silica structure is then vacuum-impregnated with a clear polymer resin binder. This stabilizes the stone, preventing it from drying out, cracking, or breaking.
Why Jewellery Makers Love Sterling Opal:
Sterling Opal is highly sought after by bench jewellers because it is physically more stable and durable than natural mined opal. It resists cracking and crazing, and it safely tolerates much higher heat levels, making it far easier to set into sterling silver or gold without the risk of breaking.