Costco offers our members high quality jewelry at an exceptional value. Our team of GIA Graduate Gemologists inspect every diamond to ensure it meets Costco's strict quality standards. We only sell natural and untreated diamonds.

Antique cuts actually tend to be less expensive than modern cut earth-mined diamonds if and when you can find them. Part of this reason is because they don't require new mining and all of the associated costs that come with that.

Andy Johnson - Owner - diamond cellar holdings | LinkedIn.

In most cases, a diamond engagement ring or other diamond jewelry will have a resale value of between 20 and 60% of the amount it cost when it was new.