Crystal Harris -- Pawn Queen

6/25/2011 7:42 AM PDTby TMZ Staff Crystal Harris is angling to cash in on the $90,000 engagement ring Hugh Hefner slipped on her finger ... with a little help from a San Diego jewelry store.Our jewelry spies were there when Harris stepped inside Prospect Jewelers in La Jolla, CA, asking for an appraisal on the ring.The owner asked Harris if there was any documentation on the quality of the ring (cut, clarity, etc.,) but the playmate was in the dark. So Crystal called over to the Playboy Mansion -- on speaker phone -- for info on the ring.  The person on the other end of the line offered to fax Crystal the info -- but not immediately -- so Crystal left.Our spy overheard the owner telling Crystal he was sorry to hear about Hef, to which Crystal replied, "Are you kidding? It was all for publicity."WHAT? Their love wasn't real??? Get out!!!!