Larimar

Discovered in the Dominican Republic and named for the discover's daughter (“Lari-ssa”) and the sea (“mar”), Larimar is a type of pectolite, which is a silicate that has, in this case, a volcanic orgin. These stones are so valuable that they are often sold by the carat, like faceted stones.
Despite its ethereal beauty, Larimar is extremely temperamental and difficult to cut: It chips, spalls, and generally does its best to foil lapidary efforts. Also, the larger the piece, the more difficult it is to avoid showing some matrix, as well as the natural healed fractures common to this stone.  In cases where these imperfections are more apparent, I have discounted the piece. This stone is considered photo-sensitive, so it should not be left out in direct sunlight for long periods or its color will fade.