About October's Birthstones

October is one of the few months blessed with two birthstones: opal and tourmaline. Both gemstones are celebrated for their remarkable range of colors, making them among the most visually diverse gemstones in the world.

Opal, derived from the Sanskrit word "upala" meaning "precious stone," is famous for its play-of-color, where flashes of rainbow hues dance across the surface as the stone is moved. No two opals display exactly the same pattern or color combination, making each stone uniquely individual.

Tourmaline, whose name comes from the Sinhalese word "turmali" meaning "mixed colored stones," can occur in more colors and color combinations than any other gemstone. From rich reds and pinks to vibrant greens and blues, tourmaline's color spectrum is truly extraordinary.

As October birthstones, opal and tourmaline are believed to bring creativity, inspiration, and protection to those born in this month. They're also traditional gifts for the 14th wedding anniversary, symbolizing the depth and variety that a mature relationship encompasses.

October Birthstone - Opal & Tourmaline

Opal & Tourmaline Properties

Physical Properties: Opal

  • Mineral: Hydrated silica (SiO₂·nH₂O)
  • Color: White, black, or fire opal with play-of-color
  • Hardness: 5.5-6.5 on Mohs scale
  • Transparency: Transparent to opaque
  • Refractive Index: 1.37-1.47
  • Crystal System: Amorphous
  • Specific Gravity: 1.98-2.20

Physical Properties: Tourmaline

  • Mineral: Boron silicate mineral group
  • Color: Virtually all colors and color combinations
  • Hardness: 7-7.5 on Mohs scale
  • Transparency: Transparent to opaque
  • Refractive Index: 1.616-1.652
  • Crystal System: Trigonal
  • Specific Gravity: 3.06-3.25

Symbolic Meaning

  • Hope: Opal's play of colors symbolizes optimism and hope
  • Creativity: Both stones are believed to enhance creative expression
  • Healing: Tourmaline is associated with physical and emotional healing
  • Love: Pink tourmaline in particular represents love and compassion
  • Protection: Historically, opals were thought to protect from evil
  • Transformation: The changing colors represent life's transitions

Sources & Origins

  • Opal Sources: Australia, Ethiopia, Mexico, Brazil, USA
  • Tourmaline Sources: Brazil, Afghanistan, USA, Madagascar, Nigeria
  • Historical Opal Source: Lightning Ridge, Australia (black opal)
  • Notable Tourmaline Mine: Paraíba, Brazil (neon blue-green tourmaline)
  • Recent Discovery: Ethiopian opals discovered in 2008
  • Formation: Opal forms in silica-rich waters; tourmaline in pegmatites

Care & Maintenance

  • Opal Cleaning: Mild soap and lukewarm water with soft cloth only
  • Tourmaline Cleaning: Warm, soapy water and soft brush
  • Ultrasonic: Never for opal; generally safe for tourmaline
  • Heat Sensitivity: Opals are very sensitive to heat and temperature changes
  • Water Exposure: Avoid prolonged water exposure for opals
  • Storage: Store separately, especially opals which can dry out

The Rich History of Opal & Tourmaline

Opals have been treasured throughout history, with the earliest known opal artifacts discovered in Kenya dating back to 4000 BCE. The ancient Romans prized opals above all other gemstones, calling them "opalus," meaning "precious stone." They believed opals contained the powers of all gemstones whose colors appeared within their play-of-color.

In medieval times, opals were considered lucky stones that could grant invisibility when wrapped in a fresh bay leaf. However, in the 19th century, opals gained an undeserved reputation for bad luck after the publication of Sir Walter Scott's novel "Anne of Geierstein," in which a character dies after her opal is touched with holy water. This superstition was later dispelled, and opals regained their popularity, especially after the discovery of Australia's rich opal fields in the 1850s.

Tourmaline has a more recent history in Western jewelry, though it has been known in China since ancient times. The name "tourmaline" was derived in the 18th century from "turamali," a word used by gem traders in Sri Lanka. Dutch traders brought tourmaline to Europe from Sri Lanka in the 17th century, but it was often confused with other gemstones until advances in mineralogy in the 19th century.

Tourmaline gained significant popularity in the late 1800s when Tiffany & Co. gemologist George Kunz began promoting the gem. The discovery of vibrant pink and green tourmalines in Maine and California around this time further increased its appeal. In the 1980s, the discovery of the electric neon-blue Paraíba tourmaline in Brazil created a sensation in the gem world, establishing tourmaline as one of the most coveted colored gemstones.

Historical Opal and Tourmaline

Opal & Tourmaline Varieties

Both opal and tourmaline come in a fascinating array of varieties, each with distinctive characteristics that make them unique in the world of gemstones:

Black Opal

The most valuable type of opal, black opal has a dark body tone (black, dark blue, dark green) that makes the play-of-color stand out dramatically. The finest examples come from Lightning Ridge in New South Wales, Australia, and can command extraordinary prices per carat.

White Opal

Also called "light opal," this variety has a white or light body color with play-of-color visible against this lighter background. While generally less valuable than black opal, exceptional specimens with vivid play-of-color can be highly prized.

Fire Opal

Known for its warm body color ranging from yellow to orange to red, fire opal may or may not display play-of-color. The most famous fire opals come from Mexico and are valued for their intense, saturated colors even when they lack the typical opal play-of-color.

Boulder Opal

This variety forms in ironstone boulders as thin seams. Cutters often leave some of the natural ironstone backing attached to the opal, creating a natural backing that highlights the play-of-color. Boulder opals are primarily found in Queensland, Australia.

Paraíba Tourmaline

The most valuable variety of tourmaline, Paraíba tourmaline displays a vivid neon blue to green color due to the presence of copper. Originally discovered in the Brazilian state of Paraíba in the 1980s, similar copper-bearing tourmalines have since been found in Mozambique and Nigeria.

Watermelon Tourmaline

This distinctive variety displays pink in the center surrounded by green, resembling a slice of watermelon. This natural color zoning occurs during the crystal's formation and makes for striking jewelry pieces that showcase nature's artistry.

Rubellite

This pink to red variety of tourmaline maintains its color in all lighting conditions, unlike some pink tourmalines that can appear grayish in certain lights. The finest rubellites have a vibrant raspberry red color without brown undertones.

Indicolite

Blue tourmaline, known as indicolite, ranges from light to dark blue, sometimes with a slight greenish tint. Fine specimens with pure blue color are rare and highly valued in the gem market.

Fascinating Facts About Opal & Tourmaline

Opal's Water Content

Opals contain up to 20% water trapped within their silica structure. This is why they must be protected from heat and dry conditions, which can cause them to crack or "craze" as they lose moisture.

Tourmaline's Electricity

Tourmaline is pyroelectric and piezoelectric, meaning it can generate an electrical charge when heated or put under pressure. This property led Dutch traders to use tourmaline to pull ash from their meerschaum pipes, as the heated gem would attract the ash particles.

Opals on Mars

NASA's Mars Reconnaissance Orbiter discovered opal deposits on Mars in 2008, which is significant because opal forms in the presence of water, supporting evidence that water once existed on the red planet.

Tourmaline's Color Range

Tourmaline occurs in more colors and color combinations than any other gemstone. In fact, an ancient Egyptian legend tells of how tourmaline traveled along a rainbow, collecting all of its colors along the way.

Opal & Tourmaline in Jewelry

Both opal and tourmaline make stunning jewelry pieces, though they require different considerations due to their varying physical properties:

Opal Jewelry Considerations

  • Protective Settings: Due to opal's relative softness (5.5-6.5 on the Mohs scale), protective settings like bezels or halos are recommended to prevent damage.
  • Everyday Wear: Opal is better suited for occasional rather than everyday wear, especially in rings which are more exposed to impacts.
  • Doublets & Triplets: Opal doublets (thin opal layer with backing) and triplets (thin opal with backing and clear cap) are more affordable and durable alternatives to solid opals.
  • Metal Pairings: Opals pair beautifully with both yellow and white metals, with white metals often enhancing the play-of-color in lighter opals.

Tourmaline Jewelry Considerations

  • Durability: With a hardness of 7-7.5, tourmaline is suitable for all jewelry types, including everyday rings.
  • Color Showcasing: Settings that allow light to enter from multiple angles best showcase tourmaline's pleochroism (different colors when viewed from different angles).
  • Bi-color Designs: Jewelry designs that highlight bi-color or watermelon tourmaline's natural color zoning can create striking, unique pieces.
  • Metal Pairings: Pink tourmalines look stunning in rose gold, while green tourmalines pair well with yellow gold, and blue tourmalines pop against white metals.

Care Tips for October Birthstone Jewelry

  • Clean opal jewelry with a soft, damp cloth only. Never use ultrasonic cleaners, steam, or harsh chemicals.
  • Store opals away from heat sources and with a small amount of moisture (some collectors keep them with a damp cotton ball in a sealed container).
  • Clean tourmaline with mild soap and warm water using a soft brush.
  • Avoid exposing both stones to harsh chemicals, including household cleaners and hairspray.
  • Remove jewelry before engaging in activities that might subject the stones to hard impacts or extreme temperature changes.

Monthly Birthstone Chart

Looking for a quick reference to all birthstones? Check out our printable birthstone chart featuring all 12 months and their corresponding gemstones.

View Birthstone Chart
Monthly Birthstone Chart