Natural Swiss Blue Topaz 26.88 ct – Octagon Cut, Certified

Natural Swiss Blue Topaz 26.88 ct – Octagon Cut, Certified

10.424,00 CZK

Gemstone Specification

Carat Weight 26.88

Dimensions 18.90 x 15.00 x 9.70 mm

Color Blue

Clarity Eye Clean

Shape Octagonal

Treatment Irradiated (All Blue Topaz worldwide is always Irradiated)

Origin Brazil

Certification Gemological Laboratory Certificate

This 26.88 carat natural Swiss Blue topaz from Brazil reveals a vivid and saturated blue hue, cut into a refined octagonal emerald shape measuring 18.90 × 15.00 × 9.70 mm. With eye clean clarity, the gemstone offers superb brilliance and transparency, while the step-cut faceting emphasizes its depth and elegance. Its striking Swiss Blue shade has been achieved through irradiation, a safe and industry-standard treatment used for all blue topaz varieties. Certified by an independent gemological laboratory, it comes with professional verification of authenticity and quality. With its impressive size and bold color, this gemstone is ideal for bespoke statement jewelry, such as cocktail rings or pendants, or as a highlight in a gemstone collection.

Natural Swiss Blue Topaz 26.88 ct – Octagon Cut, Certified

10.424,00 CZK

From gemstone to jewelry

This example illustrates one possible way a gemstone may be developed into a bespoke piece. Final design is always defined individually, based on the stone and its natural character.

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Each gemstone is professionally examined and accompanied by clear gemological information regarding its characteristics, treatments, and origin.

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Gemological overview

Technical and gemological information about this gemstone variety.

Gemological profile

Topaz is a silicate mineral valued for its clarity, durability, and broad color range, which includes colorless, blue, yellow, brown, pink, and imperial hues. In gem-quality material, topaz is appreciated for its clean appearance and ability to be cut into precise, well-defined shapes that emphasize brilliance and transparency.
Chemically composed of aluminum fluorosilicate (Al₂SiO₄(F,OH)₂), topaz crystallizes in the orthorhombic crystal system and belongs to the silicate mineral group. Gem-quality specimens typically display a vitreous luster with transparent clarity.
The refractive index of topaz generally ranges from approximately 1.61 to 1.64, resulting in bright light return and a crisp visual appearance. Topaz is found in several regions worldwide, with notable sources including Brazil, Pakistan, Russia, Sri Lanka, and Nigeria, depending on the specific color variety.

Durability & suitability

With a hardness of 8 on the Mohs scale, topaz offers very good resistance to scratching, making it suitable for a wide range of jewelry applications when properly set and worn with standard care. It performs reliably in rings, pendants, earrings, and bracelets.
Despite its hardness, topaz has perfect cleavage, meaning it can be sensitive to sharp impact if struck at certain angles. For this reason, protective settings are recommended for rings, particularly for larger stones. When thoughtfully set, topaz combines durability with refined brilliance, making it suitable for both everyday jewelry and more expressive, statement-oriented designs.

Treatments & authenticity

Topaz is commonly treated to enhance or modify color, particularly in blue varieties, where irradiation followed by heat treatment is widely used and accepted within the gem trade when properly disclosed. These treatments are stable and do not compromise the structural integrity of the gemstone.
Any treatments or enhancements are always clearly stated for each individual gemstone. Every stone is professionally examined, and transparent disclosure is regarded as a fundamental part of responsible gemological practice, allowing clients to make informed and confident decisions.

Our approach to gemstones

We focus primarily on natural, untreated gemstones, valued for their authenticity and inherent beauty.
Any treatments or enhancements are always clearly disclosed, allowing our clients to make informed decisions based on transparent gemological standards.

Sosna Gems is not a licensed financial advisor. Gemstones are collectibles, not securities. Past performance is not indicative of future results. Legal & risk disclosure .