Opals are very interesting and there are some myths that you’ll want to know about as well. We even have some spectacular specimens for you to admire as you learn about this fascinating gemstone. Was the opal the ancient Romans admired the same as the one we admire today? No one is sure. However, evidence of opal artifacts date as far back as 4000 B.C. Though the exact cause of opal formation is still disputed, many believe that silica was carried down into rock crevices by heavy rains. Once the water evaporated, what was left was a silica gel that then hardened over the course of what some believe is millions of years. This didn’t happen overnight! It takes roughly 5 million years to solidify just one centimeter of opal. This theory makes sense considering opal has water in it. The water content of an opal can be upwards of 20 percent but is usually in the 5 percent range. There are two types of opals: precious and common. Precious opals either have vibrant color (fire opal) or exhibit a play of color. Play of color is a term coined to describe the unique multi-dimensional color display that the more precious opals have. The other colors are caused by the way silica forms together. Silica is composed of a bunch of tiny spheres that adhere to one another. When they fuse, tiny gaps are created between them that allow the light to diffract. This diffraction causes a magnitude of different shapes and color combinations. Opals that have the most intense and diverse play of color are generally the most expensive and prized. Boulder opal is the only opal that can display the entire rainbow within one stone. That’s at least seven colors if you count indigo. Not only is there a birthstone from every month, there are Zodiac birthstones as well. The birthstones that apply to your Zodiac sign are not as defined as the monthly birthstones that were cemented by the National Association of Jewelers. Many cultures throughout history have associated different gemstones with astrological signs. The stone that aligns with your sign largely depends on which list or culture you choose to follow. Opal has commonly been associated with the signs Scorpio and Libra, which aligns with October. Opal is also the official gemstone gift alternative for the 14th wedding anniversary.
