Custom Engagement Rings And Jewelry Store in Houston. DCI is one of America’s few diamond houses open to the public by appointment only. We specialize in crafting custom engagement rings, wedding rings and more. The best part about our diamonds is that they're bonded, so you'll never lose value. Come back 10 years from now with a diamond you purchased from us and we'll buy it back at the price of its original value! Stop by and see why we've become internationally known for our diamond buying experience!