A certified or tested gemstone is one which goes through a series of test in an accredited Gemmological lab equipped with variety of instruments like polariscope, refractometer,spectroscope,microscope etc under the supervision of qualified and experienced gemologist fully equipped to identify natural, synthetic, immitation and all sort of treated gemstones.

Gemmological laboratories exist all over the world wth some of the renowned ones established by gemmological association of america and asian institute of gemmological sciences etc.

Pakistan has also got several gemmological labs in major gemstone hubs.

Certificate issued by any gemmological laboratory having gemmological equipment along with qualified and experienced gemmologist is credible. The certification of gemstone safeguard you from being getting ripped off by forgery or cheating thus enabling you in getting reliable stones and as the saying goes "Better a diamond with a flaw than a pebble without".

It is also necessary to get a authentic gemstone as some people buy them for astrological use.