Gemological Laboratory Services Ltd.

Gemological Laboratory Services Ltd. GLS Lab is a leading UK-based laboratory offering excellence in gemological analysis and certification.

With a commitment to integrity and precision, GLS provides a range of services tailored to meet international standards.

Amber is a remarkable organic gemstone formed from ancient tree resin that has polymerised over millions of years, often...
17/11/2025

Amber is a remarkable organic gemstone formed from ancient tree resin that has polymerised over millions of years, often preserving prehistoric life with exceptional clarity. Inclusions such as the mosquito showcased here act as natural time capsules, offering rare scientific insight into ancient ecosystems and biological evolution. Natural Baltic amber, known for its succinic acid content and warm golden hues, is valued for both gemological significance and jewellery craftsmanship. Its internal flow patterns and natural textures reveal its geological journey.

Topaz, a gemstone of dazzling brilliance and strength, captivates with its spectrum of colours and exceptional clarity. ...
09/11/2025

Topaz, a gemstone of dazzling brilliance and strength, captivates with its spectrum of colours and exceptional clarity. Among its many varieties, Imperial Topaz and Blue Topaz stand as timeless icons of beauty and refinement. Imperial Topaz, the rarest and most treasured form, glows with rich golden to pinkish-orange hues born from trace elements of chromium and iron — a natural masterpiece found mainly in the historic mines of Ouro Preto, Brazil. Blue Topaz, in serene shades from Sky to London Blue, achieves its mesmerising tones through expertly controlled irradiation and heating, resulting in stable and enduring colour. Both embody nature’s artistry and human ingenuity, uniting rarity with radiance.

Phenomenal Gemstones are those that exhibit distinctive optical effects caused by the interaction of light with the gem’...
02/11/2025

Phenomenal Gemstones are those that exhibit distinctive optical effects caused by the interaction of light with the gem’s internal structure. These effects arise through mechanisms such as reflection, refraction, interference, and diffraction, often influenced by inclusions, structural layering, or crystallographic orientation within the mineral.
Such phenomena include asterism, chatoyancy, adularescence, aventurescence, labradorescence, iridescence, and orient—each revealing how light behaves uniquely in different gem species. At Gemological Laboratory Services Ltd (GLS), these effects are scientifically observed, documented, and reported with precision, ensuring every gemstone’s optical character is accurately understood and authenticated.

Celebrated as October’s birthstone, the Opal is a gemstone of extraordinary character. Its mesmerising play-of-colour ha...
19/10/2025

Celebrated as October’s birthstone, the Opal is a gemstone of extraordinary character. Its mesmerising play-of-colour has inspired myths, poetry, and royal collections throughout history. No two opals are ever alike — each holds a unique spectrum of fire within. At GLS, our experts use advanced gemological analysis to detect treatments, distinguish between natural and synthetic opals, and ensure complete transparency for traders, jewellers, and collectors. From Australia’s black opals to Ethiopia’s crystal opals, our certification guarantees authenticity and confidence in every stone.

Padparadscha sapphires: Flame-fusion or flux-grown? 💎 Discover the differences in quality and price.The flame-fusion (Ve...
03/09/2024

Padparadscha sapphires: Flame-fusion or flux-grown? 💎 Discover the differences in quality and price.

The flame-fusion (Verneuil) method produces synthetic padparadscha sapphires in large quantities, but the quality is generally lower compared to those made using the flux-grown method. The flame-fusion process uses alumina oxide mixed with chromium and iron for coloration. A natural 1 carat padparadscha sapphire is valued at around £5,000 GBP, while a 1 carat flame-fusion synthetic costs about £50 GBP, and a flux-grown synthetic is priced at around £150 GBP. Flux-grown padparadscha sapphires, made with Al2O3, Cr, Fe, and a MoO3 flux, result in vibrant, transparent gems. Chatham Created Gems Inc. excels in this method, producing top-quality synthetic padparadscha sapphires.

Treatment enhances the color of lower-grade Padparadscha stones. While heat treatment is acceptable, methods like irradi...
24/08/2024

Treatment enhances the color of lower-grade Padparadscha stones. While heat treatment is acceptable, methods like irradiation and lattice diffusion are not, as they alter the gem-stone's natural color.

Padparadscha Sapphires: The Rare and Enchanting Lotus GemSapphires come in a wide range of colors, including yellow, gre...
15/08/2024

Padparadscha Sapphires: The Rare and Enchanting Lotus Gem

Sapphires come in a wide range of colors, including yellow, green, and purple, due to the presence of elements like iron, titanium, and chromium in their aluminum oxide composition. Among them, Padparadscha is the most prized, known for its rare and beautiful blend of orange and pink hues. This gemstone, originating from Sri Lanka and named after the Sanskrit word for "lotus color," is highly valued for its exceptional quality and cultural significance. While Padparadscha sapphires can also be found in Madagascar, Tanzania, and Vietnam, Sri Lankan ones are preferred for their ideal pink-orange balance.

There’s ongoing debate about the exact color definition of Padparadscha, but it’s generally agreed they should display a subtle mix of pink and orange with pastel tones and medium saturation. Their durability, brilliance, and clarity further enhance their appeal, making them highly desirable in the world of gemstones.

12/08/2024

Peridot, a gemstone with extraterrestrial connections, has been found in 4.5 billion-year-old pallasite meteorites and comet dust, It has also been identified on the Moon and Mars collected by the Stardust robotic space probe and NASA’s Global Surveyor. Astronomers believe that extraterrestrial olivine crystals as the mineral form of peridot, formed near stars in the hottest parts of the universe.

The value and quality of peridot are predominantly determined by its color, with the most desirable specimens exhibiting an intense green hue with balanced tone and saturation. Stones that are free from visible inclusions or blemishes are considered more valuable, and larger stones are rarer and therefore more highly prized.

Peridot forms in iron and magnesium-rich basalts and crystallizes in the orthorhombic system, making it notable for its geological and gemological significance.

Peridot may include biotite, chromite, pyrope garnet, spinel, or liquid and gas inclusions. Characteristic features of peridot are disk-like fracture inclusions known as "lily pads" and strong doubling.

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28 Greville Street, Hatton Garden
London
EC1N8SU

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Monday 10:30am - 5:30pm
Tuesday 10:30am - 5:30pm
Wednesday 10:30am - 5:30pm
Thursday 10:30am - 5:30pm
Friday 10:30am - 5:30pm
Saturday 10:30am - 5:30pm

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