12.85 Ct. Black Opal from Australia

This specimen is a Black Opal in a freeform configuration, weighing 12.85 carat, with dimensions of 15.75 x 19.68 x 5.42 mm. The material is opaque, presenting a multi color play with dominant green and blue fields, and an overall medium intense color intensity. The cut is not applicable in the traditional faceted sense, as the piece is a shaped cabochon style freeform, intentionally retained to preserve the color bar orientation within the slice. Enhancement is by doublet construction, and origin is Australia. The surface finish is an excellent polish, achieved to maximize luster and to present the opal layer with minimal surface scattering. These parameters make the piece particularly well suited to collectors and designers who require a stable, visually striking opal slice with predictable mounting considerations.

From a lapidary and material science perspective, the doublet architecture is central to the performance and handling of this piece. The precious opal layer is bonded to a darker backing substrate, which serves to deepen perceived body tone and increase apparent brightness of the play of color. The thickness of the opal layer and the quality of the bond are crucial variables, affecting durability and visual continuity. In this example the opal layer maintains sufficient thickness across the field to show broad color patches and a degree of rolling flash when viewed from different angles, while the backing provides contrast without apparent light leakage. Polishing was executed with progressively finer diamond abrasives followed by a felt and cerium or tin oxide final polish, producing the excellent polish noted. Because the cut is freeform, the lapidary left slightly chamfered edges and a controlled dome to balance weight retention and surface area for color display. Orientation of the opal plane is optimized to present the strongest color when mounted face up, and the 5.42 mm thickness is adequate for bezel retention while still allowing low profile settings.

Practical guidance for setting, care, and design integrates the optical and mechanical characteristics of this doublet Black Opal. For long term stability and protection of the thin opal layer, bezel mountings are preferred over prong settings, as bezels support the perimeter and reduce point stresses. Avoid ultrasonic cleaning, steam, aggressive solvents, and prolonged exposure to high heat, because these can compromise the adhesive layer in doublets and alter the opal surface. Gentle cleaning with mild soap and warm water, and drying with a soft cloth, is recommended. For jewelry applications, this piece functions particularly well as a pendant or a generously proportioned left right matched earring component, and it can be set into rings provided the design includes protective rims and shock absorbing settings. From a valuation and grading standpoint, the piece should be considered for its medium intense color brightness, multi color palette, and overall polish quality, with the doublet enhancement recorded in any appraisal or sales documentation. This Black Opal is offered by The Natural Gemstone Company, and the supplied technical description aims to assist gemological assessment, design integration, and appropriate care for sustained appearance and performance.