The Gem Certification Assurance & Lab is now offering a “zero tolerance” guarantee on its diamond grading reports—meaning if its graders don’t deliver the same opinion twice, it will refund the difference to consumers.

Originally GCAL had offered a one-grade guarantee—which caused skepticism, since experts noted it is very rare for a lab to be more than one grade off. But with the new guarantee, a consumer may resubmit the original, undamaged diamond to GCAL for two years following its certification, and if GCAL finds its weight or other grade is lower than on the original certificate, GCAL will reimburse the difference in retail market value between the two grades.

GCAL’s parent company, Collectors Universe, has four divisions offering similar guarantees. Last year, it paid out $391,000 under those guarantees after certifying $1.7 billion in high-value assets. Collectors Universe CEO Michael Haynes told analysts in a conference call he thinks the company’s new jewelry division will be profitable by the end of fiscal 2007.