12 x 8mm average size. RARE-beautiful Golden Herkimer Diamond pendants. These natural quartz stones get their golden color when small petroleum inclusions form. No two alike, check out the enlargement to see the variations in size and clarity.The bail and prong setting are sterling silver with a touch of rhodium which helps prevent tarnish. These pendants are made with an A grade Golden Herkimer Diamonds. Herkimer Diamonds are quartz formations which because of their brilliance and diamond shape have been given the name. Herkimer diamonds help release energy blockages and also help enhance dream recall. Really nice!