Large Swarovski crystal AB square clasp

Cut like a diamond, looking into vintage Swarovski article 2650 is like looking into a deep pool, it goes on forever. This is predominantly a crystal, but there are flashes of green and blue like the fire in an opal. This clasp is perfectly flat on top. The faceting is all inside. The centerpiece came to me in its original box labeled D.S. & Co. The vintage centerpiece is bezel set in a hand-made sterling silver box clasp.The clasp is 10 mm high, 19 mm wide and 33 mm from ring to ring.