What is an Opal and How Does It Get It’s Unique Coloring?

Opals are some of the most unique gemstones in the world, but how are they created and why do they look different than other gemstones? Noe’s Jewelry in Raymore, Missouri, is here to answer all of your opal-related questions.

What is an Opal?

Technically, opals are a non-crystalline form of mineral silica. They belong in the same family as quartz and agate, but differ for these two stones, because they are formed as amorphous lumps of silica instead of naturally faceted crystals. Opals are considered a precious gemstone, along with diamonds, rubies, sapphires, emeralds, and pearls.

These gemstones are most commonly found in Australia—so much so that 95 percent of the opals on the planet are in Australia. In the United States, opals have been found in Arizona, Oregon, Utah, Idaho, Louisiana, and Nevada. There are also places in South America, Central America, Africa, Europe, and Asia where opals are mined.

There are two main varieties of opal: precious and common opals. When you think of opals in jewelry, you are thinking of precious opals. Common opals are more common in nature but are dull and have no value. The characteristic bouncing of color that precious opals are known for is missing from common opals.

How Are Opals Created?

In nature, opals are created from a solution of water and silicon dioxide. Water seeps through sandstone and picks up particles of silica. Millions of years ago, this solution filled the cracks and voids in sedimentary and volcanic areas in Australia. Over a period of another million years or two, the rock solidified and formed opal.

Opals get their unique coloration due to the loss of water in the solution in which the silica was deposited. The solution starts to form a gel, and the silica starts to form spheres in the gel. The spheres are uniform in size and packed in to form a very orderly pattern, but because they are round, there are small cavities that allow for diffraction of light.

The diameter of the silica spheres gives the opal its specific color. If the spheres are large, the opals will show red or orange colors. If they are very small, blues are diffracted. Everything in between will show various other colors of the rainbow. This is called play-of-color.

Opals in History

It isn’t just modern humans that have a love for these unique gemstones. Throughout history, opals have been popular with some of the most well-known historical figures around the world.

Marc Anthony sent a Senator to exile when the Senator refused to sell Marc Anthony an opal that he wanted for Cleopatra. Shakespeare even wrote about opals in Twelfth Night.

In the 1800s, Queen Victoria brought about a resurgence of love for opals. She often gave opals as wedding gifts, and she and her daughters made them part of a fashion trend.

If you are looking for an opal of your own in the Kansas City area, stop by Noe’s Jewelry. Noe’s has an array of opal jewelry that can suit any style and budget. From estate jewelry, to the brand new Le Vian opal pieces, Noe’s will help you find the perfect opal for you.