Marina's 3.8ct Cushion Cut Black CZ Engagement Ring The black rhodium electroplating will eventually wear off and need to be re-plated. We offer a 30 day Guarantee, No Questions Asked. You may get a replacement or a refund by simply contacting customer service. The .925 sterling silver ring features an elegant black tone design. Features a Simulated black diamond cushion cut CZ measuring 3.87-carats. The stunning black CZ is surrounded by a halo of clear CZs, which also highlight the band by extending partially down each side.