October Birthstone: Opal and Tourmaline

October is an introspective month of in-betweens: the sunlight fades earlier, the leaves shift from lush greens to golden oranges, and the air holds warmth in the afternoon but offers a chill by evening. It’s fitting, then, that the October birthstones embody this feeling of transformation. Opal, with its kaleidoscopic fire, and tourmaline, with its rainbow of hues, are stones that resist singular definition. Together, they speak to October’s liminality: a season of change, deep thought, and brilliance.

What is October’s Birthstone?

The modern list of birthstones recognizes two for October: opal and tourmaline. Opal, long the traditional choice, is celebrated for its play-of-color, a phenomenon where light breaks into shimmering flashes of green, blue, orange, and red. Tourmaline, introduced later as an alternative, offers a spectrum of shades from delicate pinks to bold greens and even the whimsical watermelon variety. Though the stones may seem quite different, they both reflect October’s spirit of balance, creativity, and renewal.

The History and Meaning of Opal

The word “opal” is rooted in the Sanskrit upala, meaning “precious stone,” passing through Greek and Latin before becoming the name we know today. Ancient Romans prized opals as symbols of hope and purity, while medieval Europeans believed in their protective powers, calling them the “eye stone” for their connection to vision.

By the 20th century, opal was firmly enshrined as the October birthstone. This placement makes a lot of sense: opal's meaning is tied to transformation, creativity, and light, qualities that mirror the shifting season.

Victoire de Castellane, the Artistic Director for the Jewelry department at the House of Dior, has said of Opals that they are her favorite gemstone because they already contain all the colors in the world. How's that for an endorsement of this very special stone? 

How Opals Are Formed and Where They Are Found

Unlike crystalline gemstones, opals are formed from silica-rich water that seeps into rock crevices. As the water evaporates, silica spheres remain, trapping light in a unique way that creates opal’s signature play-of-color.

Most opals today are mined in Australia, which produces more than 90% of the world’s supply. Other important sources include Ethiopia, Mexico, Brazil, and the United States. Each region gives rise to distinct varieties: Australian black opals with dark, vibrant flashes, Ethiopian opals with translucence and fluid fire, and Mexican fire opals glowing in orange and red.

Characteristics of Opal: Color, Shape, and Fire

No two opals are alike. Some flicker with delicate blues and greens, while others burn with vivid reds and oranges. Their surfaces often carry milky or transparent backgrounds, where color can dance in beautiful and unpredictable ways. Opals are most often cut into cabochons (smooth, rounded domes) that highlight this play-of-color. Rating between 5.0 and 6.5 on the Mohs scale, opals are much softer than most other stones and require protective settings and care. This fragility is part of their allure: a reminder that beauty often lies in the most delicate things in life. For collectors of opal jewelry, the uniqueness of each stone is the draw. An opal necklace, a pair of opal earrings, or opal rings all promise individuality; no two are ever the same.

Opal’s Astrological Significance

Astrologically, October belongs to Libra and Scorpio, two signs in tension. Libras seek harmony and balance, while Scorpios embrace intensity and transformation. Opal, with its shifting fire, reflects both. For Libras, it’s a stone of creativity and clarity; for Scorpios, it magnifies passion and depth. Wearing opals is said to amplify these qualities. In times of change, opal becomes a talisman of adaptation, an emblem of October’s energy.

Tourmaline: The Other October Birthstone

While opal often claims the spotlight, tourmaline is an equally fascinating October birthstone. Unlike opal’s fluid fire, tourmaline is crystalline, belonging to a complex group of silicate minerals. Its name comes from the Sinhalese word turmali, meaning “stone of mixed colors,” a fitting description for a gem that occurs in nearly every hue imaginable.

Tourmaline Formation and Sources

Tourmaline forms in granite and pegmatite, developing in long, slender crystals. Its wide color range comes from trace elements: iron and titanium create greens and blues, manganese creates pinks and reds, while copper yields neon “Paraíba” tourmaline, one of the most prized varieties. Brazil remains the most significant producer, though notable deposits are also found in Afghanistan, Mozambique, Nigeria, and the United States (particularly Maine and California).

Tourmaline Historical and Cultural Significance

Tourmaline has been treasured since the 1600s, when Dutch traders brought stones from Sri Lanka to Europe. For centuries, its colors were so varied that it was often mistaken for other gems: red tourmaline passed for ruby, green for emerald. In spiritual traditions, tourmaline has been considered a stone of protection and grounding. Ancient mystics believed it could shield the wearer from negative energy while enhancing balance and compassion.

Characteristics of Tourmaline

Tourmaline’s most distinctive quality is its color diversity. It can be found in soft blush pinks, rich emerald-like greens, oceanic blues, dramatic blacks, and even bicolor or tricolor crystals. The famed watermelon tourmaline blends pink and green in concentric rings, resembling the fruit for which it is named. This versatility allows October babies to choose a stone that truly reflects their personality. In terms of hardness, tourmaline ranks 7–7.5 on the Mohs scale, making it more durable than opal and well-suited for daily wear. Stones are often faceted to emphasize clarity and brilliance, though cabochon cuts highlight unique color zoning.

Astrological Significance of Tourmaline

Where opal reflects creativity and shifting light, tourmaline offers grounding energy. For Libras, it supports emotional balance and harmony; for Scorpios, it channels intensity into focus and strength. Its rainbow palette makes it a stone of inclusivity, adaptability, and personal expression, qualities that align beautifully with October’s spirit of transformation.

October Birthstone Jewelry

When it comes to October birthstone jewelry, opal and tourmaline lend themselves beautifully to a diverse set of designs. Opals, with their shifting play of color, are often found in rings, their domed cabochon cuts capturing the eye with flashes of fire. A vintage opal ring from the Edwardian or Art Deco periods often pairs the stone with diamonds, adding both sparkle and protection. Tourmaline, by contrast, is a sturdier gem, and jewelers often facet it to maximize brilliance. Whether in a deep green or soft pink, a tourmaline ring offers clarity and vibrancy that feels as timeless as it does contemporary.

Necklaces showcase the personalities of both stones differently. An opal necklace adds a radiant, but soft glow to the face of the wearer, its colors shifting with the light. A faceted tourmaline pendant delivers sharp flashes of green, pink, or even the playful pink-and-green contrast of watermelon tourmaline. 

Earrings bring another layer of beauty to both of the October birthstones. Opal earrings shimmer with every turn of the head, their rainbow fire catching light close to the face. Tourmaline earrings, by contrast, tend to play with color in a more direct way: pink tourmaline drops or green tourmaline studs offer bold yet wearable hues. 

At Jack Weir & Sons, we’ve spent the last 40 years traveling to Europe and all over the world, curating extraordinary estate jewels. JWS is where the old world meets the new world. Celebrate life, preserve history, and discover your own priceless heirloom jewel. We are extremely grateful for our clients and the ability to help people celebrate their special moments through one-of-a-kind jewelry. To share that gratitude and our strong family values, we chose to partner with Baby2Baby. So far, we've donated $125,000. A portion of every sale goes towards children living in poverty to provide them with diapers, clothing, and all the basic necessities that every child deserves. 

We offer in-person and Virtual Appointments and are happy to answer any questions about your favorite jewel. 

JWS Flawless Protection Plan: 

• • Free Sizing & Overnight Shipping
  • 7-Day 100% Return Policy 
  • 30-Day Exchange for Credit
  • Free Appraisal with Purchase
  • 100% Authenticity Guaranteed