4.76 Ct. Cabochon Carnelian from Brazil

This specimen is a translucent red carnelian weighing 4.76 carats, presented in a round shape with precise dimensions of 10.93 by 10.92 by 5.43 millimeters, reflecting near perfect symmetry between the two measured diameters and a dome height that is approximately 50 percent of the diameter. The stone is fashioned as a cabochon, exhibiting a well centered apex and a high dome profile that optimizes optical depth and color saturation, characteristics desirable in fine cabochon work. The material is a cryptocrystalline form of silica, chalcedony in the carnelian variety, with a vivid color intensity that presents as a rich red field when viewed under standard lighting, and an eye clean clarity grade determined at normal viewing distance, indicating an absence of inclusions visible to the unaided eye. The piece has been enhanced by dyeing, a disclosed and documented treatment, applied to deepen and homogenize the red tone, and it displays an excellent polish, yielding high surface luster and smooth tactile feel that are consistent with professional lapidary finishing.

From a cutting and craftsmanship perspective, the cabochon demonstrates controlled material removal and precise curvature, achieved through sequential grinding, smoothing, and polishing stages on progressively finer laps. The dome profile was likely established using a fixed radius wheel or a series of incrementally finer wheels to ensure concentric curvature and uniform symmetry, minimizing windowing and ensuring even light transmission across the face of the stone. The polishing phase, responsible for the excellent polish noted, would have employed diamond pastes for initial high point removal followed by a final polish using a silica based compound such as cerium oxide or aluminum oxide, applied on a soft leather or felt pad to bring out the optimum refractive sheen typical of chalcedony. The translucency interacts with the dome geometry to produce a saturated apparent color when viewed face up, while the internal scattering of light characteristic of chalcedony contributes to the depth of tone without sacrificing clarity.

Regarding treatment and stability, the dyeing applied to this carnelian is a common and stable enhancement for chalcedony varieties sourced from Brazil, intended to intensify natural hues and achieve uniformity across the stone, the dye penetrates micro fissures and the fibrous cryptocrystalline matrix, improving visual appeal, while remaining relatively stable under normal wear conditions. End users should be advised that exposure to strong oxidizing agents, prolonged immersion in harsh chemicals, or repeated exposure to extreme heat may affect surface treatments, therefore routine jewelry care involves avoiding household chemicals, limiting exposure to steam and ultrasonic cleaners, and considering protective settings such as bezels that minimize direct impact and abrasion. Verification of dyeing can be undertaken using standard gemological techniques, including visual examination under magnification to detect concentration in fissures, UV inspection for fluorescence anomalies, and spectroscopic methods for confirming organic dyes.

In addition to the carnelian details described, our catalog includes opal specimens of the White Opal type, a hydrous form of silica noted for its light body tone and potential for play of color, with physical properties and care requirements that differ from chalcedony based gems, white opals commonly display a light body color with diffraction based play of color when internal microstructure is well ordered, they typically have lower hardness and greater sensitivity to dehydration and thermal shock than carnelian, therefore when pairing this vivid red carnelian with a white opal in complementary designs, consideration should be given to protective mounting and avoidance of aggressive cleaning methods. The Natural Gemstone Company provides this carnelian with full disclosure of enhancement, precise measurements and weight, and provenance identified as Brazil, a source known for producing high quality carnelian material with well defined color zoning that responds predictably to cutting and surface treatments. For jewelers and collectors seeking a cabochon with a high dome, vivid color, eye clean clarity, and an excellent polish, this carnelian represents a technically sound choice, and further gemological documentation can be supplied on request to support setting and conservation decisions.