0.73 Ct. Blue Sapphire from Tanzania

This 0.73 carat cushion shape blue sapphire from Tanzania is a superb example of how natural structure and expert cutting combine to produce exceptional sparkle. The stone measures 5.18 by 5.15 by 3.04 millimeters, is faceted with a mixed brilliant cut, and displays a medium color intensity with very slightly included clarity, evaluated at eye level. As corundum, the sapphire crystallizes in the trigonal system and possesses a high refractive index around 1.76 to 1.77, along with a modest birefringence of 0.008 to 0.010. These intrinsic optical properties, together with a Mohs hardness of 9, give this sapphire both the brilliance and durability prized by educated collectors. The mixed brilliant cut, applied to a cushion outline, balances large table and crown facets with a pavilion designed to return maximum light, producing scintillation and depth that exceed what is typical for standard step cuts. The excellent polish ensures facets act as flawless mirrors, enhancing the interplay of light and giving the gem a lively, faceted fire that reads as unmatched when viewed in hand and on the finger.

For the discerning buyer, the value of this sapphire lies in its combination of natural origin, clarity, cut quality, and stability of enhancement. Heat treatment has been used to optimize color, and this is an industry standard, stable enhancement that does not compromise the structural integrity of the corundum lattice. The very slightly included clarity grade means the stone reads clean to the eye, preserving transparency and light return while also confirming its natural origin and character. The medium blue saturation is versatile, flattering in both white and yellow metal settings, and the cushion mixed brilliant proportions make it an ideal candidate for a classic solitaire or as a refined center stone in a halo design. At The Natural Sapphire Company we place emphasis on accurate grading and ethical sourcing, and this Tanzanian sapphire exemplifies the attributes experienced buyers seek, namely optical performance, durability for everyday wear, and investment potential due to its precise cutting and natural origin. This gem will appeal to collectors and connoisseurs who appreciate the way geological structure and masterful cutting come together to create an enduring and brilliant jewel.