Amethyst engagement rings? Absolutely! Diamonds may be a girl's best friend, but Amethyst engagement rings are a unique, original, and a far more affordable choice. As the gem of peace and tranquility, amethyst is mesmerizingly beautiful. A durable and affordable gem, an amethyst ring is excellent for every day wear. This birthstone of October has a luminosity and glow that makes an opal the treasure that it really is. The rainbow of colors on a neutral white background makes an opal ring a perfect match for any outfit.