Depending on the conditions in which it formed, opal may be transparent, translucent, or opaque, and the background color may be white, black, or nearly any color of the visual spectrum. In ancient times opal was included among the noble gems and was ranked second only to emerald by the romans. Explore the vibrant world of gemstones
Learn about the different types of opal and where to find them in our comprehensive guide. Opal, silica mineral extensively used as a gemstone, a submicrocrystalline variety of cristobalite Photos of opal from around the world
Opal gems are so unique you’ll need a special vocabulary to describe them Learn all about the many opal varieties and how to evaluate them.
