The International Gemological Institute (IGI) announced it now provides
QR (quick response) codes for IGI-certified jewelry. The code will link
to an article’s unique IGI report, which can be conveniently viewed with
a smartphone. 
Proof that is is real, proof that the quality is as mentioned.
Certification of such products is needed to deliver this proof. When buying or selling the presence of this certificate will definitely speed up the transaction process.
If this certification per product is placed online, and accessible via a QR Code, you could just place various pieces of jewelry in your storefront, with just a little QR Code accompanying the product.
By just scanning the QR Code your (potential) customer will be able to see the certification of the piece displayed.
A nice service that can be easily be enhanced by using a branded QR Code, with a company logo, or an image displaying the product itself.
 Quoted from www.diamonds.net