Proprietary Grading Systems

The development and introduction of Gemfields Proprietary Rough Grading System has revolutionised the coloured gemstone sector, by delivering a consistent supply of various coloured gemstones for the very first time. The gemstones are meticulously sorted and precisely graded, before being brought to market by way of private auctions.

Going into detail, Gemfields mined gemstone rough is sorted in to nearly 200 different grades of emerald & beryl, whilst we have nearly 500 different grades of ruby & corundum. Each piece of gemstone rough is hand sorted for colour, size and quality, and checked against the Gemfields reference sets to ensure consistency.

Discover Our Gemstones

GRADING
OF EMERALDS

The rough emerald and beryl is sorted into four primary grades:

Premium emerald
Emerald
Beryl one
Beryl two

There are over 200 grades of various sizes, qualities and colours. The Gemfields grading system has been developed over the years at the Kagem mine. We have set the standard for ourselves, after extensive interaction with our customers, so that we are able to deliver a consistent supply to the market and to ensure that our gems are best positioned to achieve their true value.

GRADING
OF RUBIES

The rough ruby is separated into various size fractions. The product is divided into two streams:

Primary product
Secondary product

The primary product is from the original source, where the rubies were mined from the host rock whereas the secondary product is recovered from gravel beds, having previously been transported through water and deposited some distance from its original place of formation. The Primary products are usually higher in volumes and lower in overall quality, against the Secondary products which are generally of higher quality but found in lower quantities.

There are over 500 grades of various sizes, qualities and colours.

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