Octagon Faceted Amethyst Crystal Necklace on 925 Sterling Silver Chain. This necklace features a large 36.38 carat amethyst crystal, surrounded by 10 fire opals. Amethysts are known to represent purification and connection to spiritual and divine beings. The meaning of amethyst is attached to serenity, understanding, trust and grace. Fire opals are said to represent the joy of the heart. View Photos for Further Details.