Gold Necklace with Gold Cross, Two Amethysts, and an Emerald Plasma, 6th?7th century, Byzantine, Gold, amethyst, emerald plasma, Overall (chain): 17 5/8 x 1/2 x 3/16 in. (44.8 x 1.2 x 0.4 cm), Metalwork-Gold, The cross, chased into the gold ground, w