October has two birthstones: opal, famous for its play-of-color, and tourmaline, which comes in pink, red, green, blue and multicolor crystals.
Opal was October's primary stone on the 1912 American list, with tourmaline already named as its alternate. Jewelers of America describes tourmaline as a 1952 addition, so accounts differ on the exact date, but the two stones now appear side by side. The pairing gives the month two kinds of color: opal's shifting flashes, and tourmaline's broad range of solid hues, including reds and greens that suit the turn of the season.
Europeans long regarded opal as a symbol of purity, hope and truth, and Bedouin lore said it held lightning and fell from the sky during thunderstorms. Tourmaline's name comes from the Sinhalese toramalli, a stone with mixed colors. Old lore claimed it inspired artistic expression, and pink tourmaline in particular is commonly associated with love and compassion. It is also the traditional gem for an eighth wedding anniversary.
Opal is hydrated amorphous silica, meaning it lacks the crystal structure of most gems. Its trademark is play-of-color, flashes of spectral hues that move as the stone turns, seen against white or black backgrounds; fire opal adds an orange body color. At 5–6.5 on the Mohs scale it is relatively soft. Australia, Ethiopia, Mexico, Brazil and the United States are notable sources.
Tourmaline is a group of related minerals rather than a single species, which accounts for its pink, red, green, blue and multicolored stones. It rates 7–7.5 on the Mohs scale and is generally suitable for everyday wear. Brazil leads the list of notable sources, along with Afghanistan, Pakistan, Nigeria, Mozambique, Madagascar, Kenya, and California and Maine in the United States.
Opal asks for the most caution in October. Clean it only with warm soapy water, protect it from high heat and sudden temperature changes, and keep assembled doublets and triplets out of long soaks. Opal also scratches easily, so it deserves its own compartment. Tourmaline is sturdier for daily wear, but it still should not go into an ultrasonic or steam cleaner, and heat can damage it.
| US list | UK list | Japanese list (2021) |
|---|---|---|
| OpalTourmaline | Opal(Tourmaline) | OpalTourmaline |
Tourmaline in any color counts on the Jewelers of America list. Some sources, including the UK's National Association of Jewellers, specify pink tourmaline, and pink is the color traditionally associated with love and compassion.
Tourmaline, at 7–7.5 on the Mohs scale, holds up better than opal, which measures 5–6.5 and is sensitive to heat and sudden temperature changes. Opal is well suited to pendants and earrings; for a ring worn every day, tourmaline is the more forgiving stone.
JanuaryGarnet
FebruaryAmethyst
MarchAquamarine
AprilDiamond
MayEmerald
JunePearlMoonstoneAlexandrite
JulyRuby
AugustPeridotSpinel
SeptemberSapphire
OctoberOpalTourmaline
NovemberTopazCitrine
DecemberTurquoiseTanzaniteZirconBirthstones are a jewelry and cultural tradition, and their meanings are folklore. Gem facts are compiled from public material by GIA, the American Gem Society and Jewelers of America.