6.66 Ct. Blue Sapphire from Ceylon (Sri Lanka)

This oval blue sapphire presents a tangible combination of weight and measured proportions, the 6.66 carat weight being a defining attribute of its rarity and market value. The gem measures 12.73 by 9.75 by 6.06 millimeters, yielding a length to width ratio of approximately 1.31, which provides a balanced oval outline that reads larger face up than its carat weight might imply in smaller proportions. At 6.66 carats this sapphire crosses a key threshold in the colored stone market, where supply diminishes and collector demand increases, making every millimeter of face up area and every fraction of a carat materially important to the stone s overall value. The depth of 6.06 millimeters produces a depth to average diameter ratio of approximately 53.9 percent, a well judged proportion that maintains strong color saturation while avoiding an over deep body that would diminish apparent size.

The mixed brilliant cut execution demonstrates deliberate cutting strategy to maximize light return and color intensity for a Ceylon sapphire of this weight. The crown is faceted with modified brilliant facets to create a lively, scintillating table field, while the pavilion geometry uses a blend of step and modified facets that preserve weight and enhance internal reflection, producing flashes of blue that shift with viewing angle. The cutter s decisions on facet size and placement were driven by the rough s natural color zoning and inclusions, optimizing the face up distribution rather than sacrificing carat weight to achieve theoretical ideal symmetry. The polish is graded as excellent, resulting in sharp facet junctions and minimal surface luster loss, which is critical in a higher carat stone because surface condition directly affects perceived depth and brilliance.

Clarity is described as very slightly included, evaluated at eye level, which in practical terms means the stone is transparent and clean to casual inspection, with only minor inclusions that do not interrupt the internal light pathways. Those minor inclusions often assist the cutter in orienting the pavilion and crown to maximize color concentration and to avoid windowing or dark areas, a particularly important consideration in a 6 plus carat sapphire where internal features are more visible. The vivid color intensity reported is characteristic of well finished Ceylon material, showing a vibrant blue saturation with lively tone that reads both deep and bright when set. Heat treatment, as disclosed, is a stable and widely accepted enhancement, used to relieve iron manganese complexes and to homogenize color, particularly effective in Sri Lankan rough where heat can unlock the typical vivid hues without compromising durability.

Provenance from Ceylon, craftsmanship, and the 6.66 carat weight together define the rarity profile of this sapphire. Stones from Sri Lanka at this weight and with vivid color intensity are comparatively uncommon, and the market premium for eyeclean material grows disproportionately as carat weight increases, because larger clean material is exponentially rarer than smaller equivalents. For collectors and connoisseurs evaluating investment quality, the combination of significant carat weight, well considered mixed brilliant cutting, very slightly included clarity, excellent polish, and Ceylon origin positions this gem as a high value piece within its class. At The Natural Sapphire Company we prioritize transparent documentation of proportions, cutting style, clarity and treatment, because each of these technical factors materially influences both immediate visual performance and long term market desirability.