Who We are?

A True Value For Your Diamond!
People from All Over the World Send their Diamonds to the ZGL Laboratory for Grading and Analysis. Our Clients Put their Business in Our Hands andtheir Trust in Our Expertise – and We Are Extremely Careful with Both.

Reliability, Experience And Passion.
ZGL Laboratories are respected diamond grading laboratory. We have pioneered the development ofthe first scientific system used to evaluate How Well adiamond Has Been Cut. Adiamond’s Cut isthe Most Important C ofAll ofthe Four C’s. When adiamondis Well Cut It Reflects and Refracts Light tothe Maximum Degree. ZGL Has Been Acclaimed asa Worldwide Innovator Due to Our Extensive Research and Development in Determining the Cut Grade of Diamonds.

ZGL Certificates

ZGL Laboratory processes undertaken with the rules of civic trust organization which promotes fairness in business, belong exclusively to business conduct fair, credible and transparent.

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ZGL pearls certificate

ZGL have equipped ourselves with the most technologically advanced equipment available for the use in the identification and authentication of colored gemstones. ZGL laboratories are equipped with immersion cells, micrometers, spectroscopes, Polaris copes, refractometers, specific gravity liquids, binocular microscopes and spectrophotometer, Each ZGL colored gemstone certificate clearly states whether the stone is natural or synthetic. The certificate identifies the variety of the gemstones its shape, carat weight, cut, color, quality, measurements, transparency factor and major optical characteristics. If the stone has undergone any treatment, this information will be listed on the certificate as well. Upon request, the origin of the gemstone may be determined.

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ZGL Diamond certificate

The ZGL diamond certificate provides a reliable and accurate documentation of a diamond's identity and grade based on the internationally recognized diamond grading system. Using state-of-the-art equipment, each diamond is analyzed by several gemologists in order to provide the most accurate description of the diamonds quality and characteristics. The carat, color, clarity and cut-commonly known as the 4c's of each diamond are clearly stated on each diamond certificate. Additional grading characteristics such as finish, girdle, culet and fluorescence are also detailed on the certificate. A diagram of diamond displaying any inclusions is also included on the certificate.

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ZGL matched pair of diamonds certificates

As every experienced gemstone collector knows-there's no such thing as two perfectly matching diamonds which are identical in all respects. But it's possible, albeit rare, to find flawless gemstones which are very close to perfect matches. When looking at the similarity of gems, the four c's of each diamond needs to be compared-that of carat, cut, clarity and color. Ideally a pair will have been cut out of the same rough stone, and by the same cutter. Matching pairs are very rare in nature - particularly since both transparent and fancy color diamonds are rare to find in the first place. And the higher the grade of diamond, the harder it will be to find another to match it-finding one perfectly cut, flawless diamond is a rarity, but finding two is an exceeding rare occurrence-these appearing only every few years.

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ZGL jewelry certificate

The ZGL Jewelry certificate is used to document jewelry pieces and identity the characteristics of the precious stones featured in each piece. Each ZGL jewelry certificate features a description of the jewelry piece followed by the statement of the characteristics and grading of the precious stones found in the piece. A statement listing the quantity of gemstones featured in the piece as well as grading report of the gemstone's weight, shape color, clarity, cut, proportions and measurements are featured in the ZGL jewellery certificate. In addition, the identification, weight and content of any precious metals found in the piece are described on the certificate. As a further way to identify jewelry piece, the ZGL certificate features an enlarged color photograph of the item. Upon request, the international gemological laboratory can easily convert an ZGL jewelry certificate into an appraisal certificate.

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ZGL gemstone certificate

ZGL have equipped ourselves with the most technologically advanced equipment available for the use in the identification and authentication of colored gemstones. ZGL laboratories are equipped with immersion cells,micrometers,spectroscopes,polariscopes,refractometers,specific gravity liquids, binocular microscopes and spectrophotometer. Each ZGL colored gemstone certificate clearly states whether the stone is natural or synthetic. The certificate identifies the variety of the gemstone, its shape, carat weight, cut, color quality, measurements, transparency factor and major optical characteristics. If the stone had undergone any treatment, this information will be listed on the certificate as well. Upon request, the origin of the gemstone may be determined.