Opal rings

Opal

— a type of gemstone characterized by a significant variety of shades: white, yellow, orange, blue, green and black opals, among others, are found. Such stones are transparent (at least translucent), and the most valuable varieties — noble opals — are distinguished by a characteristic iridescent overflow, called "opalescence", named after the mineral. In addition, natural opals glow under UV light. A synthetic variety of this stone is also produced, some of these crafts are almost indistinguishable from naturally occurring opals.