When Craig Underwood buys a diamond with a grading report, he reviews the document—and then promptly files it away. Like a growing number of retail jewelers, the Fayetteville, Ark.–based owner of Underwood's Fine Jewelers has begun to offer clients his own in-house diamond evaluations because he can't always reconcile the discrepancies between diamond grading reports from different gem labs.Underwood and other ­jewelers adopting this practice tell JCK they're committed to presenting customers with certificates of replacement or detailed store receipts instead of diamond grading reports or lab certificates."We'll give the customer a lab-issued diamond grading report if the customer specifically asks for it, but that rarely happens," Underwood says. "Most of the time the lab-issued grading report is filed in our archives and never shown to the customer. The only report the customer re