5 Fascinating Facts About Opal, October’s Birthstone
There’s a reason opal has fascinated people for centuries. Unlike most gemstones, opal doesn't simply have one color—it can seem to contain an entire rainbow within a single stone. Move an opal in the light and flashes of green, blue, pink, orange, yellow, and purple may suddenly appear.
October’s birthstone is one of nature’s most colorful creations, and its history and formation are just as interesting as its appearance.
Here are five fascinating facts about opal that you may not know.
1. Opal Can Display an Entire Rainbow
One of the most distinctive characteristics of precious opal is its play-of-color—the flashes of color that appear and disappear as the gemstone is moved.
This isn't simply a reflection of color from the surface. Opal has a unique internal structure made up of tiny spheres of silica. When these spheres are arranged in a regular pattern, light interacts with them and produces the brilliant flashes of color we see.
The result can be almost magical.
One opal might show brilliant blue and green, while another displays fiery orange, red, and yellow. The pattern and colors can vary dramatically from stone to stone, which is one reason opal jewelry feels so individual.
2. Opal Is Different From Most Gemstones
Opal isn't quite like the other gemstones you may find in your jewelry box.
Unlike crystalline gemstones such as sapphire, ruby, and quartz, opal is made primarily of hydrated silica and does not have the same crystal structure.
It also contains water—typically several percent by weight.
That water is part of what makes opal so fascinating from a geological standpoint. Opal forms when silica-rich water moves through cracks and spaces in rock. As the water gradually evaporates, tiny particles of silica are left behind. Over a very long period of time, those particles can accumulate and eventually form opal.
In other words, an opal's beautiful colors are the result of an extraordinary combination of geology, water, light, and time.
3. Australia Is Famous for Its Opal
When many people think of opal, they immediately think of Australia—and for good reason.
Australia has produced some of the world's most famous opals and is home to several important opal-producing regions.
Lightning Ridge is particularly famous for its black opal, which can have an especially dramatic play-of-color against a dark body tone.
Coober Pedy is another major Australian opal-producing area and is well known for its white and light-colored opals.
Australian opal isn't the only opal in the world, however. Beautiful opal is also found in places including Ethiopia, Mexico, the United States, and other parts of the world.
Each locality can produce opal with its own distinctive appearance and characteristics.
4. Opal Has Been Admired for Thousands of Years
Our fascination with opal is certainly not new.
Opal has been collected and used for jewelry and decorative objects for thousands of years. The ancient Romans admired the gemstone and considered it particularly precious because one stone could display the colors of many others.
Throughout history, people have also attached legends and symbolism to opal because of its unusual appearance.
Its flashes of color have inspired associations with rainbows, magic, creativity, hope, and good fortune.
Like many gemstones, these meanings are part of cultural history and tradition rather than scientific fact—but they add another fascinating layer to the story of opal.
5. No Two Opals Look Exactly Alike
Perhaps the most fun thing about opal is that nature doesn't make them identical.
The play-of-color, patterns, body color, transparency, and flashes of light can vary enormously from one opal to another.
Even two pieces cut from the same larger piece of rough opal can have noticeably different appearances.
That's especially appealing when you're choosing opal jewelry. Instead of looking for a gemstone that is perfectly uniform, you're often looking for the individual personality of the stone.
A flash of blue here, a little green there, or a fiery burst of orange can make one opal completely different from the next.
Why We Love Opal at BeJeweled
For us, that's part of the fun of working with natural gemstones.
Opal is colorful, unusual, and full of surprises. It can look completely different under different lighting and from different angles, making it a gemstone that you can continue to notice and appreciate every time you wear it.
And because October's birthstone is so naturally colorful, opal jewelry makes a wonderful birthday gift—but you certainly don't have to be an October birthday to enjoy it.
Love the colorful flashes of opal? Explore our opal jewelry collection to find a unique piece of your own.