Diamonds are tested with a Presidium multi tester III which allows to differentiate Moissanites from natural Diamonds and are weighed with a Tanita scale model 1210 This diamond will be delivered to you with a bill of sale and an estimate of the characteristics of the stone This diamond does not have a certificate, the valid certificates are HRD, EGL, GIA, AGS, IGI.... , those of Antwerp or those of the Paris Chamber of Commerce ....... To be certified a stone must be sealed or not but with a traceable certificate, thethe diamond can also have a laser engraving on his girdle the laboratory logo and the certificate number. So 99% of the stones sold on ebay are without a certificate. an official certificate, it is the identity card of the stone you are buying now you find many sellers who.