Quick Answer
October has two official birthstones: opal, prized for its shifting rainbow "play-of-color," and tourmaline, a modern-era addition known for spanning nearly every color a gem can be. Pink tourmaline is considered October's signature shade. Opal is soft and water-bearing, so it suits pendants and earrings better than a ring worn every day.
What Are the October Birthstones?
October has two official birthstones: opal, the traditional stone known for its shifting rainbow "play-of-color," and tourmaline, a modern addition from 1952 that comes in nearly every color imaginable. Pink tourmaline in particular is considered October's signature shade, sitting alongside opal on both birthstone lists.
- Opal — a hydrated silica mineraloid best known for play-of-color, flashes of rainbow light that shift as the stone moves
- Tourmaline — a borosilicate mineral that spans nearly every color; added to the modern birthstone list in 1952 alongside zircon and citrine
- Pink tourmaline is the shade most closely tied to October, though any tourmaline color counts as a birthstone
- Opal has anchored the birthstone list since it was first standardized in 1912
Opal: Play-of-Color, Hardness, and What to Know Before You Buy
Opal is a hydrated form of silica prized for play-of-color — the flashes of rainbow light that shift as the stone moves, caused by microscopic silica spheres inside it diffracting light. It's softer than many gemstones at Mohs 5 to 6.5, and it holds water within its structure, so extreme dryness or heat can cause it to crack.
- Precious opal shows play-of-color; common "potch" opal doesn't flash and is valued mainly for background color, not fire
- Mohs 5 to 6.5 — softer than most gemstones, and prone to fine surface cracking ("crazing") if it dries out too quickly
- Doublets (a thin opal layer glued to a backing) and triplets (a doublet plus a clear protective cap) are assembled stones, not solid opal — worth naming honestly if you come across one
- Most opal on the market comes from Australia, with Ethiopian opal (found in the 2000s) and Mexican fire opal as other well-known sources
Tourmaline: Nearly Every Color, and Why Pink Is October's Signature
Tourmaline is a borosilicate mineral that comes in almost every color a gem can be, from deep green to bright pink to bi-color "watermelon" stones. It joined the modern birthstone list in 1952, and while any tourmaline color counts, pink tourmaline is the shade most closely associated with October.
- Mohs 7 to 7.5 — noticeably tougher than opal and suited to more regular, everyday wear
- "Watermelon" tourmaline shows a pink center ringed by green, one of the most recognizable bi-color gems
- Heat treatment and irradiation are both used to improve or shift tourmaline's color, a disclosed, industry-standard step
- The name comes from the Sinhalese "tura mali," meaning "mixed gems" — a nod to how often early traders mistook one tourmaline color for an entirely different gemstone
How to Wear an October Birthstone Look Every Day
Because opal is soft and tourmaline spans nearly every color, an October-inspired piece works best as a pendant or earrings you can layer rather than a ring exposed to daily knocks. Libra runs through most of October, so a zodiac-styled pendant is another personal way to mark the month.
Here's what we make in moissanite and 925 sterling silver to sit alongside that idea, styled for October rather than sold as opal or tourmaline:
Browse the full necklaces collection for more everyday pendant styles, or see our gift guide under $100 for more ideas.
A Custom October Birthstone Piece, Made to Order
A birthstone means more when it's tied to a specific person, not just a calendar month. We build made-to-order pieces around that idea: a numeral or initial pendant with a genuine opal or tourmaline accent, a small memorial design, or a piece made for one particular gift and nobody else's.
A nameplate style like this is a natural starting point for a custom design conversation. Start a custom design inquiry and tell us what you have in mind — we'll talk through sourcing options for a genuine opal or pink tourmaline accent.
Caring for October Birthstone Jewelry
Opal and tourmaline need different care because of how differently they're built. Opal contains water and can crack if it dries out too fast or takes a hard knock, while tourmaline's higher hardness makes it noticeably more forgiving for everyday wear.
- Keep opal away from prolonged dry heat, direct sun, and sudden temperature swings
- Skip ultrasonic and steam cleaners for opal; a soft, barely damp cloth is the safer routine
- Tourmaline tolerates warm water, mild soap, and a soft brush better than opal does
- Store pieces separately in a soft pouch so harder stones can't scratch softer ones
- Put jewelry on last, after makeup, perfume, and hairspray
For more on keeping sterling silver bright between wears, see our sterling silver and moissanite care guide, or read our August birthstone guide and September birthstone guide if you're shopping for more than one birth month this year.
Frequently Asked Questions
What is the October birthstone and what does it mean?
October has two birthstones: opal and tourmaline. Opal is prized for play-of-color, the shifting rainbow flash inside the stone, and has long symbolized hope and purity. Tourmaline, added to the birthstone list in 1952, spans nearly every color, with pink tourmaline considered October's signature shade.
Is opal really bad luck?
No — that idea traces mostly to a 19th-century novel, Sir Walter Scott's "Anne of Geierstein" (1829), where an opal talisman is linked to a character's death. It's fiction, not folklore, and opal had been prized for thousands of years before that story existed.
What's the difference between a solid opal and a doublet or triplet?
A solid opal is cut from a single piece of stone. A doublet glues a thin layer of precious opal onto a backing, and a triplet adds a clear protective cap on top of that. Both are legitimate, widely sold products — just ask which one you're buying, since they're valued and cared for differently than solid opal.
Can I wear a tourmaline ring every day?
Yes, more comfortably than opal. Tourmaline measures Mohs 7 to 7.5, tough enough for regular wear, while opal's Mohs 5 to 6.5 and water content make it better suited to pendants and earrings that see gentler daily contact.
Can MYNSU make me a custom October birthstone piece?
Yes. Opal and tourmaline aren't part of our ready-to-wear catalog, which runs on moissanite and 925 sterling silver, so a custom order is the way to get a genuine one. Tell us the stone, cut, and piece you're picturing — an initial pendant, a memorial design, a milestone gift — through a custom design inquiry, and we'll work out sourcing from there.
Every MYNSU order ships free within the US, backed by 30-day returns, and ships from our Irvine, California warehouse.