Natural London Blue Topaz 13.23 ct – Octagon Cut, Certified

Natural London Blue Topaz 13.23 ct – Octagon Cut, Certified

Name: Natural London Blue Topaz 13.23 ct – Octagon Cut, Certified
Brand: SOSNA Gems & Jewellery
SKU: GP80181
Price: 22665.00 CZK
Availability: InStock

22.665,00 CZK

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Gemstone Specification

Carat Weight 13.23

Dimensions 16.04 x 12.04 x 7.65 mm

Color Deep Blue

Clarity Eye Clean

Shape Octagon

Treatment Irradiated (All Blue Topaz worldwide is always Irradiated)

Origin Brazil

Certification Gemological Laboratory Certificate

Description

This 13.23 carat natural London Blue topaz from Brazil features a deep and sophisticated blue tone, cut into an octagon step shape measuring 16.04 × 12.04 × 7.65 mm. With eye clean clarity, the gemstone offers excellent transparency, while the precision-cut facets highlight its dramatic depth of color. Its rich London Blue shade has been achieved through irradiation, a safe and industry-standard treatment applied to all blue topaz. Certified by an independent gemological laboratory, it comes with professional confirmation of its authenticity and quality. With its impressive size, bold cut, and dark blue tone, this gemstone is ideal for statement jewelry pieces such as rings or pendants.

Natural London Blue Topaz 13.23 ct – Octagon Cut, Certified

22.665,00 CZK

Documentation & Verification

Every gemstone is supplied with the documentation stated in the product specification. This may include an independent laboratory certificate or a Sosna Gems Colored Stone Report.

Additional or alternative independent laboratory certification can be arranged upon request for eligible gemstones.

Learn about bespoke jewelry

Every bespoke piece begins with a gemstone. Selected gemstones from our collection can be transformed into individually designed jewelry, created around the proportions, character and intended use of each stone.

Every design is developed in consultation with our gemologists and goldsmiths, ensuring that the finished piece complements both the gemstone and your preferences.

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.

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