Swarovski blue Montana square clasp

Cut like a diamond, looking into vintage Swarovski article 2650 is like looking into a deep pool, it goes on forever. The predominate color is the mysterious Montana Blue. It is blue and grey and green all at the same time. 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. It is 11 mm high, 16 mm wide and 30 mm from ring to ring.