There are a plethora of industry-specific vocabulary terms used to describe gemstones and their features. Words like refraction, dispersion, base tone, and brilliance describe the qualities of a gemstone. A term exclusive to opal-terminology is called “play of color,” which refers to the way light enters the gemstone and flashes brilliantly across it in a fiery display.
For an opal to exhibit play of color, it must be a precious opal. There are common opals, but they won’t exhibit the same rainbow effect. What is play of color? We’ve briefly defined it, so keep reading as we outline the key features that make precious opals flare up like a rainbow on fire.
Play of color is an optical phenomenon that describes the interplay between opals and light. When white light enters the gemstone, it bounces across the silica spheres within and reflects a myriad of bright colors across the surface of the stone. Play of color isn’t so much an optical illusion as a simple matter of light and reflection. Still, it’s hard to believe your eyes when they land on the vivid spectacle of color before you.
Think of play of color as the interaction of the whole light spectrum bouncing around in a playful display. The colorful display is most prominent from the outside of the gemstone, but within is equally as colorful. So, how does it happen?
These multitudes of color take place when white light enters the opal and moves through the silica spheres inside the gem. The light interacts with the inner parts of opals and causes new colors to surface. Isn’t nature fascinating?
You can also recreate play of color in different settings. In fact, that’s what lighting specialists do on movie sets, and photographers do regularly. By exposing certain colors and hiding others, you can customize a light show. For example, if you see a bright blue color under one light source, you might be able to view brilliant reds or greens under another.
The angle at which you look at the gemstones might differ as well, so both lighting and angles can affect an opal’s play of color.
Every gemstone — from diamonds to opals — has objects within the gemstone that influence its coloring. These are called inclusions, and they are minerals and tiny trappings locked within the gem as it grew within the earth. When it comes time to cut rough stones into gemstones, gem cutters strategically cut into the stone to best display its colors. In many instances, they’ll deliberately cut out inclusions that might dim the gem’s coloring.
However, it takes more than a skilled gem cutter for an opal to have play of color, and that’s due to the natural formation process of the gem.
Within opals, there are naturally-occurring silica spheres that grow in layers. Different opals have different silica spheres, and that’s often a key feature that helps gemologists sort and categorize opals. The size of the silica spheres themselves are the factor that dictates the colors that leave the gemstone.
All opals have layers of silica spheres, but the layering determines whether or not an opal is considered a common opal or a precious opal. The opals with carefully layered silica spheres are precious opals, while those with sporadically-placed silica spheres are common opals.
Remember, only precious opals have play of color. and only precious opals display the play-of-color phenomenon. Who decides the silica structure of an opal, and ultimately, it’s play of color? Why, only mother nature holds that paintbrush!
So, which elite opals have the prized play of color? Let’s find out!
There are dozens of species of opal gemstones, but only a handful of them demonstrate bright play of color. Some gemstones on the list include:
Let’s have a closer look at Boulder opals and Matrix opals in action to fully bring the concept of play of color home.
Boulder opals are precious opals that express play-of-color in bits and pieces. Rather than appearing all throughout the gem, the light changes are visible in patches. Most of the time, the light causes lines of color to appear in the original stone, but this is not a prerequisite for a gemstone to be considered a Boulder opal. Rather, the colors just need to be spaced out across the rock.
Boulder opals are often found within a variety of different rock — from Andesite and Basalt to Quartzite and Rhyolite to the rare occurrence in Sandstone. Boulder opals are most commonly found in Mexico and Honduras.
Matrix opals are a category of precious opals that have colors all throughout the original gemstone. Unlike Boulder opals that display color in distinct parts of the opal, Matrix opals exhibit colors that are more evenly mixed into the gemstone. In other words, the opal looks like a colored gem rather than a gemstone with stripes of color on top.
Matrix opals are found in many parts of the world, including Mexico, Australia, and Honduras. Discoveries occur in Basalt, Claystone, Ironstone, Limestone, Quartzite, Sandstone and Rhyolite.
Are you entranced by the mesmerizing play of color seen on opals? We don’t blame you! Who can resist such a tantalizing natural phenomenon that you can actually wear in jewelry, too? When it comes to buying opals, you always want to choose a reputable jeweler who can authenticate the gemstone.
Here at Opal Auctions, we offer high-quality opals from verified opal miners and sellers around the world. Moreover, we provide extensive information, images, and history of each one of our beautiful opals. Our Opal Sheriff Program ensures that you receive opals with an approved gemological lab certification.
Ready to bring a rainbow of excitement into your life? Browse our large catalog of opals to find yours today!
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