1.68 Ct. Blue Sapphire from Ceylon (Sri Lanka)

This 1.68 carat cushion shape blue sapphire from The Natural Sapphire Company presents a precise combination of proportion and finish, offering a transparent presentation with dimensions of 8.05 by 6.36 by 3.53 millimeters. The stone has been fashioned with a mixed brilliant cut, where a brilliant style faceting on the pavilion meets a more restrained crown faceting schema. The result is a strong face up presence with broad flashes of blue, a vivid color intensity, and an excellent polish that maximizes surface luster. Clarity has been assessed as slightly included at eye level, meaning the gem remains visually clean to most viewers while retaining natural internal character. The sapphire originates in Ceylon Sri Lanka, a source known for blue material that balances saturation with lively tone. Enhancement has been performed by heat treatment, a standard and stable procedure used to even out color and improve transparency, performed with professional gemological control.

From a cutting and optical perspective the mixed brilliant faceting strategy employed here is designed to balance color saturation and light return. The pavilion facet array generates internal dispersion and scintillation while the crown facets are proportioned to open the table and allow a broad, uniform color face up. Measured proportions yield a depth of approximately forty nine percent relative to the average diameter, creating a stone that reads larger on the finger than deeper stones of the same weight, and concentrating the vivid blue in the viewing plane. Optical constants for corundum are relevant to technical buyers, with a refractive index approximately 1.762 to 1.770, birefringence in the order of 0.008 to 0.010, and a dispersion around 0.018. Specific gravity is in the range of 3.95 to 4.03, which is consistent with natural corundum and assists in distinguishing sapphire from many simulants.

Clarity and finish are important to the gemological performance of this sapphire. The slightly included clarity grade indicates small internal features are present, typically fine crystals or needle like inclusions, which can act as light scattering centers but in this specimen do not obscure transparency. The excellent polish enhances facet junction crispness and contributes to strong mirror like reflections from the crown facets. Heat treatment has been applied to improve color uniformity and to attenuate certain inclusions, and because it is a traditional and stable enhancement, it does not require special restrictions for most cleaning and setting scenarios. The provenance from Ceylon imparts certain color character, with a vivid blue that can show slight blue violet pleochroism when viewed from different crystallographic angles.

Durability is a primary consideration for everyday jewelry, and corundum performs exceptionally well in this regard. Sapphire registers nine on the Mohs hardness scale, second only to diamond which sits at ten, and substantially harder than common gem materials such as topaz at eight, quartz at seven, and emeralds which often test around seven to seven and a half but frequently present additional fragility due to included structures. Corundum lacks true cleavage planes, which reduces the risk of catastrophic splitting on impact compared with minerals that have perfect cleavage. The high hardness of this sapphire gives it strong resistance to scratching and abrasion, making it well suited for rings and other pieces intended for regular wear. For technical buyers who consider long term performance, the combination of hardness nine and stable heat treatment yields a durable, reliable gemstone whose surface resilience is excellent under typical wearing conditions.

For setting and care the proportions and mixed brilliant cut suggest specific approaches to maximize visual performance. Because the pavilion is relatively shallow, settings that lift the stone slightly above the mounting plane and allow light to enter the pavilion will enhance brilliance and color saturation. A four or six prong setting with clean bezel rails will protect the corners of the cushion shape while permitting maximum table exposure, and a halo of small accent stones can visually increase apparent size without compromising the central blue. Routine care for a heat treated sapphire is straightforward, warm soapy water with a soft brush is effective, and professional ultrasonic cleaning and steam cleaning are generally acceptable when no surface reaching fractures are present. The Natural Sapphire Company provides full disclosure of origin and enhancement, and this sapphire is an example of careful lapidary work combined with classic Ceylon color, making it an excellent choice for connoisseurs who value technical precision, durable performance, and a vivid, transparent face up presentation.