Very uncommon square Ethiopian Opal cabochon weighing 0.8 carats and measuring 6.2x5.9mm set in a Sterling silver setting with an anti-tarnish 16” Argentium silver chain. Argentium silver is purer than standard Sterling (940 or 960 parts per 1000), has increased tarnish resistance, a whiter colour, antibacterial and hypoallergenic properties and a firestain-free surface. This opal has flashes of yellow, blue, green, and orange