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Opal Types and Origins – More about the October Birthstone

black opal, opal jewelry, opals, types of opals, white opal
Opal Types and Origins – More about the October Birthstone

The main birthstones of October, opals are known for their unique display of flickering rainbow colors. In addition to their iridescent, luminous beauty, these radiant gemstones offer a diversity of choices, since they come in so many compelling forms. w

White Opal

The most common type of opal, this variety has a white background and is generally sub-transparent to translucent. It typically displays opalescence and will often show all the spectral colors. Now regarded as less valuable than black opal, white opals are still very beautiful and can command high prices. Most come from Whitecliffs, Australia and Marla, Australia, but some are found in Canada, Ethiopia and Hungary.

Black Opals

With a black body color and little to no opalescence, black opals are considered the most desirable type of opal. The dark background gives the reds, oranges and yellows beautiful contrast, creating a more compelling look. The fullness and intensity of the color contributes to higher pricing. Black opals primarily come from Lightning Ridge, Australia, but some are mined in Honduras, Hungary and the USA.

Boulder Opals

This type of precious opal occurs when the host rock forms naturally as part of the gem. With these opals, it’s not uncommon for only a thin vein of precious gemstone to be present. Boulder opals occur as in-fillings of voids or cracks usually within ironstone boulders. They can be light or black depending on the look of the stone when viewed from the surface.

The popularity of boulder opals has soared since around the mid 1970s. Boulder opals are cut in a way that incorporates the host brown ironstone. They mainly occur in specific locations over a wide swath of Western Queensland. A type of boulder opal also occurs in Andamooka, South Australia, where quartzite is the host rock. Known as painted ladies, these types of opal are normally only suitable as non-jewelry specimens.

Mixed Opal

The term “matrix opal” is used to refer to opals that are intimately diffused as infillings of holes or pores between grains of the host rock. Boulder matrix opals are found in Queensland, where the host rock is ironstone.

Found in Andamooka, South Australia, Andamooka matrix opal is another porous variety, which is generally treated to enhance the natural color using chemical treatments.

Triplets and Doublets

Triplet and doublet opals are a combination of naturally mined opals and artificial veneers. A triplet is a thin veneer of light opal bonded to a black veneer backing with a protective crystal dome glued over the top.

A doublet opal refers to a layer of precious light-colored opal bonded to a black backing to simulate black opals. Doublets are typically more expensive than triplet opals because more precious opal is used.

opal and diamond necklace

Different Colored Opals

In addition to all the aforementioned variations, opals also come in different colors. Some of the most popular include:

  • Blue Opals from from Peru, Indonesia, Madagascar, Arizona and Oregon
  • Prase Opals, a yellowish to bluish green variety from Kosovo, Tanzania and California
  • Green Opals from Australia, Peru, Mali, Madagascar, South Africa and Serbia
  • Mali Opals, a yellow-golden gem formed in the Sahara desert
  • Hyalite Opal, a glass-colored gem from Australia, South Africa, Russia, Mexico, Brazil and the U.S.
  • Pink Opal, found in Mexico and Peru
  • Caramel Spice Opal™, a coffee-colored opal from Ojuelos de Jalisco, Mexico
  • Morado Opal®, a purple opal from Mexico
  • Ethiopian Opal, a rainbow opal known as “Queen of Gemstones”
  • Fire Opal, a translucent brown, red or orange opal mainly found in North and Central South American

In addition to these, there are a variety of other opals which all get their color from different mineral inclusions.

Distinctively Beautiful Opal Jewelry

Prized for their uniquely alluring beauty, opals are available in a wide variety of jewelry pieces. Unlike many other jewelers, John Atencio hand-selects his opals and creates one-of-a-kind designs around them. While you may not be able to get every opal described in this article; our team can help you select a breathtaking piece that suits your unique preferences and style.

At John Atencio, we offer a compelling selection of opal gemstones that beautifully complement our artfully designed jewelry pieces. We also offer an intriguing selection of breathtaking pieces featuring other colorful birthstones, including emeralds, rubies, sapphires and more. Visit one of our convenient locations and let our courteous and knowledgeable jewelry experts guide you to the perfect jewelry piece for yourself or that special person on your shopping list.