Natural Blue Topaz 6.12 ct – Greenish Blue, Oval Cut

London Blue topaz, 6.12 carats, oval cut, eye clean clarity, greenish blue color, ČGL certified

6.12 ct greenish-blue topaz in oval cut, eye-clean clarity, natural gemstone

Natural London Blue Topaz 6.12 ct – Oval Cut, Eye Clean, ČGL Certified

Name: Natural London Blue Topaz 6.12 ct – Oval Cut, Eye Clean, ČGL Certified
Brand: SOSNA Gems & Jewellery
SKU: GP00513
Price: 4098.00 CZK
Availability: InStock

4.098,00 CZK

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This London Blue Topaz weighs 6.12 carats and is fashioned in an elegant oval cut, measuring 13.40 × 9.65 × 6.00 mm. The gemstone displays a rich greenish blue color, characteristic of the highly sought-after London Blue topaz variety. With excellent transparency and clarity graded as eye clean, the stone presents a clean appearance with no inclusions visible to the naked eye.

Its classic oval shape and precise faceting maximize brilliance and light return, creating vivid flashes of deep blue color throughout the gemstone. London Blue topaz is particularly admired for its sophisticated darker tone, offering greater depth and intensity than lighter blue topaz varieties. The combination of attractive proportions and vivid color makes this gemstone an excellent choice for fine jewelry.

Certified by the Czech Gemological Laboratory (ČGL), this gemstone has been identified as treated topaz, with the laboratory confirming that the color has been enhanced, a standard and widely accepted treatment used to achieve the desirable London Blue color. The combination of eye-clean clarity, elegant oval cut, vivid blue coloration, and independent laboratory certification makes this gemstone an excellent choice for collectors and bespoke jewelry creations.

Natural London Blue Topaz 6.12 ct – Oval Cut, Eye Clean, ČGL Certified

4.098,00 CZK

From gemstone to jewelry

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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 .