The Jared jewelry store has gone dark on Rockville Pike, one of 150 underperforming locations that parent company Signet decided to close. Signet, which also owns Zales and Kay Jewelers, says its biggest problem these days is the lack of demand for engagement rings. Apparently, the three-year mark is normally the time when relationships progress to the jewelry store. But Covid disrupted all that — and Signet predicts the demand for diamonds may not bounce back for another year. As for Jared’s former location in Rockville: The property is slated to eventually become part of a new residential complex. The short-term plan is still unclear.