0.80 Ct. Bi Color Sapphire from Ceylon (Sri Lanka)

This bi color round sapphire from Ceylon presents a precise set of measured and observed characteristics that are of particular interest to the technical buyer, the gem cutter, and the connoisseur. The stone weighs 0.80 carat, with a near ideal round outline measuring 5.73 by 5.75 millimeters across, and a depth of 3.45 millimeters, yielding a depth percentage of approximately 60.1 percent. The faceting is a mixed brilliant cut, a deliberate combination that places a brilliant cut crown over a pavilion that emphasizes both broad flash and controlled return, optimized for color retention in corundum. Clarity is graded as very very slightly included at eye level, indicating that minute inclusions do not disrupt transparency in typical viewing conditions, and the overall transparency is described as transparent. The color is bi color with medium intensity, showing two distinct yet harmonizing hues within the corundum matrix, and the stone has been heat treated to stabilize and enhance color, consistent with standard practices for Ceylon sapphires. The polish is excellent, indicating that facet junctions and surface finish are executed to a high standard, which supports crisp light return and minimal surface diffusion.

From a faceting and light performance perspective the mixed brilliant cut used here balances scintillation and surface brightness with face up color integrity. The crown light table and star facets are proportioned to yield controlled dispersion and a lively interplay between small pinpoint flashes and broader flashes across the table. The pavilion design has been executed to favor internal reflection over leakage, which is particularly important for a medium intensity bi color sapphire where preservation of both hues is desired. The crown to pavilion relationship, combined with a well maintained girdle thickness, allows rays entering the table to be reflected in a manner that accentuates pleochroic behavior, so that the bi color character is visible as shifts in tone and saturation when the stone is rotated or viewed from different angles. The excellent polish contributes to specular reflection from facet planes, increasing apparent brightness, while the mixed cut geometry creates a layered effect with alternating zones of contrast and flash that emphasize the duality of color rather than masking it.

Comparing reflective qualities to other gemstones in the sapphire family and to common alternatives highlights how this specimen performs in wearable jewelry. Corundum has a refractive index around 1.76, which produces moderate brilliance and lower dispersion than gemstones like diamond, so faceting strategy is central to optimizing perceived brightness. Against single tone Ceylon sapphires of equal weight and cut, this bi color round will show a more complex internal light behavior, with localized contrast between the two hues that enhances scintillation and visual depth. Compared to parti sapphires that exhibit well defined color zoning and often require large, open cuts to display their zones, this mixed brilliant treated sapphire achieves a tighter, more controlled display of color changes while retaining lively return. Against spinel and garnet of similar tone, both of which may exhibit higher or lower refractive indices and different absorption spectra, the sapphire will display a more subdued dispersion but stronger color saturation retention when set face up. In relation to faceted stones with higher dispersion, the mixed brilliant approach here trades extreme fire for structured brightness and layered contrast, resulting in a sophisticated shimmer that responds predictably to directional light, and that emphasizes color stability under daylight and incandescent sources.

From a craftsmanship and setting perspective this sapphire from The Natural Sapphire Company offers designers and jewelers a high degree of predictability. The near ideal round proportions and accurate table orientation make it well suited to classic prong settings that maximize table exposure, and the depth and mixed cutting style also allow for secure bezel or semi bezel treatments without significant loss of optical performance, provided the bezel is slim and precisely made. For customers seeking to exploit the bi color effect, siting the stone in settings that allow rotational play will showcase pleochroic shifts, whereas more static bezel settings will present a single harmonized face up color that reads as a nuanced medium intensity tone. Because the stone is heat treated, its color is stable under normal jewelry conditions, and standard care for corundum applies, avoiding prolonged exposure to strong acids or extreme mechanical abuse. For bespoke applications The Natural Sapphire Company can provide additional imaging and faceting reports to assist in setting design, and the excellent polish and very very slightly included clarity grade ensure that light return and durability are not compromised by the stone s internal structure.