These earrings contain natural White Australian Fire Opal gemstones measuring 6x8mm that are dyed, and high quality cubic zirconia's (rainbow colors are a natural effect of a white fire opal being dyed to look like black opal). These earrings are 925 sterling silver and platinum plated, also available in gold or rose gold color. Upon purchasing, please include your choice of metal color within your order notes. This item includes a gift box and a certificate of authenticity with purchase. This item is made to order, please allow 10-15 days for processing and delivery of this item.