With a rep that precedes it into the 21st century, the most well-known birthstone for the month of October is opal. Its very name is derived from either Sanskrit for "a precious jewel" or ancient Greek for "a change of color;" and the fantastical colors and almost animate play of colors and light have fascinated people for millennia. Wrapped in myth and soaked in story, this water-stone's legends are as varied as the colors that leap across its surface:
Carried to Earth by lightning.
The footsteps of the Creator, traversing the world.
The tears of a weeping god.
Metaphysically, it has been considered a lucky stone, conveying on the wearer confidence, faithfulness, and the power of prophecy. Described as the innermost flickers of a fire, an erupting volcano, the dizzying kaleidoscope of the night sky, the palette of a master painter. And for those with the love of all things astrological, you will find that opal is both a Libra birthstone as well as a Gemini birthstone.
Not too bad for simple silica!
Opal is formed when silica blends into a solution with water and flows into a rock matrix, which then partially dries, depositing spheres of silica in layers stacked like balls of varying sizes. When light hits the strangely-shaped water-filled gaps between these spheres, it is refracted into the dizzying array of colors and shapes visible in what we call precious opal. Only a 5.5-6 on the Mohs hardness scale, opal is a fragile gemstone. It keeps some of the water content from its formation, so sometimes it "crazes" or cracks under dry conditions. The best way to store opal is to keep it in distilled water away from light, which prevents that natural dehydration.
The Many Types of Opal
An important delineation between opal types is common opal versus precious opal. Common opal is the term used to describe all opal types that do not exhibit the play-of-color many people assume all opals possess. Despite being called “common,” a number of these types of opals are actually gems: the fiery orange or red fire opal being the most famous; hyalite opal (a type of water opal) being far more obscure; and blue or pink Peruvian opal, which is enjoying recent popularity in fashion jewelry\
By contrast, precious opal comprises a very widely varied collection of opal types, spanning from an understated milky opal to an extremely rare and flashy Yowah nut opal.
What kind of precious opal will your heart desire? Perhaps white opal or its dramatic opposite, black opal?
White opal is the traditional, sometimes milky stone with patches of fiery color displayed over a white background. Black opal sets those same colors against a dramatic darker backdrop, allowing the colors to shine more vividly. Boulder opal is cut so that parts of the rock matrix in which it formed are still visible in the stone, setting the colors against an opaque and differently textured ground. Mined all over the world, including in the US (Nevada's state gemstone), opals are most commonly found in Africa, Mexico and most famously, Australia, where it is the national gemstone.
This enigmatic stone has had a lingering bad reputation for almost 200 years. For two centuries, it was sad that bad luck would visit those who wore opal without having an October birth month. And considering their fragility, "bad luck"was probably a common occurrence for jewelers attempting to set them. Perhaps the jewelers themselves started the rumor of bad luck? Hmmmmm...one can only wonder.
Another culprit was the Sir Francis Scott novel published in 1822, Anne of Geierstein, wherein a Duchess wears an enchanted opal pendant that loses its powers and results in her death (and a huge drop in European opal sales).
And it's possible even DeBeers may have played a role in encouraging all of these nasty rumors about opals, as high quality opal flooding the market in the 19th century threatened to unseat diamond as the most popular gemstone choice...
October's Other Gemstone Tourmaline Isn't Just a Pretty Color - It's the Dang Rainbow
Named from a Sinhalese word meaning "stone of mixed colors", it can be found in every color of the rainbow! It is also a Gemini birthstone (particularly bicolor versions, which show "twin" colors). Ancient Egyptians believed that its many colors came to them as they traveled from the depths of the Earth to the surface, passing through rainbows on its way. Ancient magicians thought black tourmaline had a shielding property, and therefore used it to fend off negative energy and thoughts. Many today still believe it has such powers.
Tourmaline can be found in black (schorl), red or pink (rubelite), green (verdelite), blue-green or purple (Paraiba), yellow, and parti-colored (such as the watermelon variety). Tourmaline's huge array of bright attractive colors actually belong to a complex group of minerals different both chemically and physically.
Its colors may be myriad, but its properties are even more interesting: tourmalines are both pyroelectric, and piezoelectric. This means that tourmaline can be electrically charged through either heat or pressure, and that it becomes magnetized when it is!
Furthermore, the color-zoning that you see in sliced watermelon tourmaline is actually growth rings of crystals with different trace elements, forming the amazing natural color bands we see. And finally, tourmaline is pleochroic, which means it exhibits different colors when you orient the crystal different ways.
But on top of that, tourmaline is a richly-colored natural wonder. Best of all, since it's a 7-7.5 on the Mohs scale, it can be worn in daily-wear jewelry.
The Great Masquerade
The October birthstone tourmaline also has a history of mystery, since its colorful nature has led to confusion with other gemstones for thousands of years.
Up until a century ago, it was not uncommon for any beautiful red stone to be sold as "ruby" or any stunning green stone to be sold as "emerald," for example.
Tourmalines could masquerade as either, leading to its mass import to Europe and other countries, including ones containing deposits of the gem they were doubling as! Traded for decades from Brazil and Sri Lanka under false names, tourmaline's popularity reignited with new discoveries in California and Maine.
George Kunz (the same mineralogist responsible for identifying the Yogo Sapphire), sold large quantities of green Maine tourmaline to Tiffany's in NYC, sparking a huge tourmaline craze.
Empress Cixi of China was such a fanatic collector of rubelite that when the Chinese empire collapsed in 1912, it destroyed the market for pink California tourmaline. It was repopularized in the 1980s when impressive finds of tourmaline near Paraiba, Brazil yielded stones of such amazing, neon blues, greens, and purples, that they amazed collectors around the world.
At present, the largest producers world-wide include Brazil, the United States, and Africa.
Mysterious and colorful, mythic and marvelous, October's spectrum of gems is suited for all jewelry mavens.
Now, when someone asks you, "What is October's birthstone?" you can tell them that there are two, and that they share the quality of magnificent, resplendent color.