Precious coral is not your usual saltwater coral. Corallus Rubeus is a gem quality red or pink coral that is hacked and polished to form jewellery. Worn throughout the centuries as adornment, it is widely documented in portraits as early as 1400s: http://www.boredbard.com/historicaljewelry/N87history.htm More recently, Black Coral and Gold Coral have been added under this umbrella term.
It's raw natural beauty is highly prized by lapidary enthusiasts as it presents endless possibilities to the mind in creating something new and beautiful. In the usual polished bead form, it resembles pearls (another organic gem). I would love to get a whole coral in a polished form. The golden coral from Hawaii is a fairly new and rare breed known for it's mystifying chatoyance.
It all very tropical. You can almost feel the island breeze brush past.