All Rebecca jewelry is crafted using daringly novel materials- bronze bathed in 18 karat yellow or rose gold, stainless, and sterling silver. The majority of their colored stones are hydrothermal creations unsing particles of semi-precious stones to recreate their crystallization. Stones 1 carat or less are natural amethyst, citrine, peridot, blue topaz, smoky quartz, garnet, black onyx, quartz crystal, iolite, tourmaline.