Certificates for central gemstones depend on a particular gem - some of them come with GIA certificates, and some have IGI. In our gemstone stock, we always mention if the particular gemstone comes with a laboratory certificate. You can browse the collection of certified gemstones in our actual inventory. Natural and lab grown diamonds, as well as moissanites - all starting from 0.5 ct always come with certificates.
If a particular gemstone doesn't have certificate mentioned in a description, this can be done by a request and the additional fee. Please use this listing for the additional IGI certificate.
For small gemstones (accent, side gemstones) there's no practice to certify them.