11.55 Ct. Boulder Opal from Australia

One beautiful opaque 11.55 carat trillion shape multi color opal is presented with precise dimensions of 18.10 x 16.59 x 5.08 mm, cut as a tablet to preserve and amplify the stone s intrinsic play of color. This is a Boulder Opal from Australia, retaining natural ironstone matrix on the reverse plane, providing structural stability and a striking contrast that enhances the vibrancy of the color display. The trillion outline has been executed with exacting symmetry, each side balanced to maintain optical center and to maximize light interaction across the broad table. The tablet cut yields a shallow crown and a broad, flat table, allowing the opal s intense internal diffraction to be viewed with minimal surface distortion, while subtle beveling along the girdle transitions into the ironstone backing to protect the stone during setting. No enhancement has been applied, the material is wholly natural, and its opaque body tone provides an ideal dark ground against which multicolored flashes register with exceptional immediacy.

From a gemological standpoint, this specimen has been graded with a clarity of very slightly included, evaluated at eye level, indicating that any natural inclusions are minor and do not detract from overall appearance except under magnification or close scrutiny. Color intensity is classified as intense, the play of color showing rapid, saturated flashes across the visible spectrum, with dominant hues that shift between rich greens, deep blues, fiery oranges, and occasional red accents as the stone is rotated under light. The tablet cut strategy was deliberately chosen by experienced cutters to orient color seams parallel to the table, producing broadflash and pinfire like patterns that read vibrantly at jewelry scale. The polish is excellent, executed to a high glass like finish that maximizes surface luster and optical transmission, and the stone s finish lines and facet junctions are clean, reflecting the cutter s focus on preservation of opal material and on minimizing unnecessary removal of the precious color bar.

Craftsmanship considerations emphasize long term visual performance and practical wearability, especially given the inherent properties of Boulder Opal. The retained ironstone backing substantially reduces the tendency toward crazing and provides a robust substrate, making the stone suitable for secure bezel or channel settings that further protect the girdle and edges. For mounting, a low profile bezel or a protective halo design will preserve the tablet geometry while allowing the table to remain the primary viewing plane. As a natural, untreated opal from Australia with no enhancement, this gemstone offers both immediate aesthetic impact and long term collectible value, particularly for connoisseurs who prioritize provenance and intact natural structure. Routine care recommendations include avoiding prolonged exposure to extreme heat, rapid thermal change, and harsh chemical solvents, and refraining from ultrasonic cleaning, all measures that will help this opal maintain its stability and surface condition over decades. The combination of precise tablet cutting, intense multicolor play, very slightly included clarity, and excellent polish ensures that this 11.55 carat trillion Boulder Opal will continue to captivate with shifting color and light, offering enduring visual appeal and collector grade presence, available through The Natural Gemstone Company.