Emerald Sterling Silver Scallop Necklace May birthstone Camp Sundance Gem Bliss. Emerald, a Beryl, is the most expensive green gemstone. Chromium is primarily responsible for the green hue in these gems. Emerald, a precious gem, is the May birthstone. For your consideration, nine Emerald briolettes in this Sterling Silver Scallop necklace, 19.5 inches long. Green Emerald Heart Briolettes 7-5mm, with minor pitting, which is preferred as these imperfections show the stones have not been treated. They are faceted opaque dark green, a forest or hunter green with some slight black veining. I have hand wire wrapped them using fine Sterling Silver wire to secure them to the Sterling Silver Scalloped part of the necklace, which is trimmed with green Onyx, green Aventurine and an easy on/off toggle clasp from Camp Sundance Gem Bliss. Matching earrings are also available.