1/3 ct Round-Cut Opal Pendant By Danny - October 6, 2015 523 Use Coupon Code: SALE and get free shipping. Delicate but with a little bit of dazzle, treat yourself to this opal pendant. A 1/3 ct round-cut opal is set in 10K gold. Piece measures 3/8 by 3/16 inches. Comes with a 10K gold 16-inch rope chain.