Opal: October's Mystical Birthstone

Opal: October's Mystical Birthstone

Posted by Craig Roberts on Oct 5th 2020

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Image Courtesy of GIA

"There are as many worlds as there are kinds of days, and as an opal changes its colors and its fire to match the nature of a day, so do I." -John Steinbeck           

This month, we're taking a closer look at October's birthstone, opal. Opal can resemble scattered confetti, the iridescence of a dragonfly wing, or the blue-green jewel tones in the ocean. Once believed to be the luckiest of all gemstones, opals have captured the imaginations of many throughout the centuries. Read on to learn more about this playful gemstone.

Opal and Diamond Cocktail Ring

Opal History and Lore

Opals were believed to be the most magical gemstone, as they can display all colors.

Ancient Greeks believed that opals possessed the power of prophecy.

According to Arabic legend, opals fall down to earth in lightning flashes.

During the Middle Ages, it was believed that wearing opal would preserve blond hair color.

Opals are the official stone of Australia and Nevada.

Opal is the birthstone for October and the 14th wedding anniversary stone.

Opal Characteristics

Opal forms below the earth's surface. Opal is composed of silica that has hardened over time. When silica dehydrates, the mineral hardens to form opal. Opals are classified as either common or precious. Precious opals display play-of-color, common opals do not. Similar to how water droplets in the sky can form a rainbow, the play-of-color characteristic is the result of light bending between stacked silica spheres. Red play-of-color is the most rare; thus, it is the most prized. Opals that display a vibrant suite of colors are highly prized. Opals have a hardness of 5 to 6.5 on the Mohs scale, making them suitable for earrings and necklaces. Opal bracelets and rings should be worn with care.

Opal doublets and triplets are sometime used in jewelry. A doublet is a layer of opal backed with another material, such as onyx or glass. This process is implemented to improve durability and enhance the opal's appearance. In a triplet, a clear covering is added to a doublet to further strengthen durability and protect the opal.

There are several different opal categories recognized by gemologists and jewelers worldwide; however, there are five main categories:

White Opal: These typically have a white background color with varying amounts of play-of-color.

Black Opal: Black opal is the rarest kind of opal. It naturally has a darker body color, varying from gray to black. The play-of-color effect is more noticeable in black opals, due to the darker background.

Fire Opal: These stones typically showcase an orange, yellow, brown or red body color. Play-of-color may or may not be present in fire opal.

Boulder Opal: Mined from ironstone boulders beneath the earth's surface, boulder opals are mined in Queensland, Australia. Boulder opal has a brown body color. Color play is typically very vibrant in boulder opal.

Crystal or Water Opal: This opal is nearly transparent without a distinct body color. Play-of-color is present in crystal opal.

Opal Information

Hardness5 to 6.5
ColorTranslucent, Multi-Color
Top Countries
of Origin
Australia, Mexico, Ethiopia

Opal Care

When it comes to cleaning opal jewelry, using a soft brush/cloth and warm soapy water is the best method. Opals are one of the softer stones, so it is not safe to place opal jewelry in an ultrasonic or steam cleaner. 

Vintage Opal and Diamond Ring

Add some opal magic to your collection. Shop our opal pieces here.