2.49 Ct. Boulder Opal from Australia

This specimen is a 2.49 carat, trillion shape, Boulder Opal originating from Australia, presented by The Natural Gemstone Company. The stone measures 10.33 x 10.64 x 2.99 mm, and is classified as opaque, with no enhancement recorded. The cutting style is a tablet cut, executed to a precise triangular outline that preserves a low profile and a broad display surface. The tablet cut in this instance is designed to maximize the viewing plane of the opal seam, providing an even field for play of color while maintaining the natural ironstone backing characteristic of authentic boulder opal. The overall finish is described as excellent polish, indicating a high degree of lapidary finish without surface abrasions or polish haze, and the color intensity is rated as intense, reflecting a high brightness and saturation in the visible play of color.

Optical characteristics of this multi color opal include dominant blues and greens with dynamic flashes that shift as the viewing angle changes, and occasional tertiary hues that emerge along microfracture boundaries and in areas of varying thickness. The play of color displays broad flash and patchy flame patterns rather than isolated pinfire, which is consistent with a thicker opal layer within an ironstone matrix. The tablet cut produces a near planar crown, which emphasizes broadflash behavior, and the thin edge profile transitions into the natural brown ironstone, providing strong contrast that enhances perceived color saturation. Color orientation has been controlled during preforming to present the most intense color across the face of the trillion, with the lapidary selecting an area of opal seam that yields even color distribution and minimal color zoning. Surface quality is excellent, the polish delivers mirror like reflectivity without micro pits or polish lines, and the stone exhibits stable play of color under standard lighting, with high brightness levels under both natural daylight and LED light sources.

From a craftsmanship and mounting perspective, this tablet cut Boulder Opal benefits from the inherent backing of ironstone which increases resistance to chipping and mechanical shock relative to freeform opal slices. The stone thickness of approximately 2.99 mm at the deepest point recommends a setting that supports the perimeter and crown, such as a full bezel or a channel inlay, to protect the edges and thin tablet profile. Prong settings are possible but should be designed to avoid concentrated pressure on the tablet edges, because opal material has a Mohs hardness in the range of 5.5 to 6.5 and remains more brittle than a typical faceted gemstone. Typical lapidary work completed for this piece includes careful trimming of excess matrix, precision sanding through progressive grits to remove subsurface abrasions, and final polishing using a cerium oxide or diamond paste regime to achieve the high gloss finish. Care recommendations include avoiding sudden thermal shock, prolonged exposure to household chemicals, and ultrasonic cleaning, all of which can compromise opal integrity. This untreated Australian Boulder Opal is offered with full disclosure of origin and enhancement status, and The Natural Gemstone Company can provide additional detailed imaging and orientation views upon request to assist with design and setting decisions.