How does the refractive index of the top layer material affect the appearance of the opal?

Shop Beacon of Courage Ring II™ in Austrailian Opal Triplet - Designed by Janyl Sherman handmade in Bali Indonesia, this Sterling Silver Chainlink & High ... Buy Ross-Simons Blue Opal Triplet Drop Earrings in 14kt Yellow Gold and other Drop & Dangle at Amazon.com. Our wide selection is elegible for free shipping ... Triplet Earrings ... An Opal Triplet is composed of a thin slice of crystal opal sandwiched between a quartz or glass top and a backing made of black potch or man ... Opal Triplet. $425.00 $250.00. Gorgeous Green Blue 1.64 Ct. Opal Triplet. Measures 7.7 mm x 3.1 mm. Add to cart. SKU: OPL 1.64ct Category: Wholesale Loose ... Feb 26, 2025 ... irenebyrneandco on February 26, 2025: "We've just manufactured this bespoke 'Sweetheart' Opal triplet necklet in sterling silver. Australian Triplet Opal Sterling Silver Pendant Material: Sterling Silver Size: 10.5mm x 20mmOpal: 9mm x 7mmCome with Sterling Silver Chain (Length: 45cm) ... Doublets and Triplets can be a fantastic alternative to solid Australian Opal, given they are far less expensive than solid Black Opals. These stunning pendants are made from quality triplet opals sourced from Australia and encased in a yellow gold setting. Each triplet opal consists of three ... Girlfriend Present Natural Black Triplet Opal Pendant Solid 925 Silver 7.88cts ... Australian Opal Natural Black Triplet Opal Earring With FREE JEWELLERY BOX!!! This mesmerizing brooch contains a black opal triplet, with excellent play-of-color, that is bezel set and bordered with a twisted rope detail.