December has three birthstones: sky blue to green turquoise, blue to violet tanzanite, and zircon, which the American list names in blue.
December started with turquoise in 1912, with lapis lazuli as the alternate. Zircon was added in 1952, by most accounts replacing lapis lazuli, and tanzanite followed in 2002, making December one of three months with three stones. Jewelers of America specifies blue zircon, so all three share a cool palette that suits winter, from turquoise's sky blue to the violet tones of tanzanite.
Turquoise has been prized since ancient Egypt. In European tradition a turquoise ring carried the message "forget me not," and in Tibet the stone is regarded as a treasure. Zircon has its own long history: medieval lore linked it with warding off evil spirits, it is one of the nine gems of the Hindu navaratna, and Victorians favored the blue variety. Tanzanite stands apart as a modern gem with no ancient lore at all.
Turquoise is a hydrated copper aluminum phosphate, and its colors run from sky blue through greenish blue to green. At 5–6 on the Mohs scale it is relatively soft, and because it is porous, it is often stabilized. Notable sources are China, Iran, and Arizona and Nevada in the United States. It is also the traditional gem for an 11th wedding anniversary.
Tanzanite is the blue to violet variety of zoisite, often showing a bluish purple tone. Its story is unusually recent and unusually local: it was identified in 1962, comes only from the Merelani Hills of Tanzania, takes its name from that country, and reached the jewelry world in 1968. It measures 6–7 on the Mohs scale and abrades easily. It is the 24th-anniversary gem.
Zircon is a natural mineral and should not be confused with cubic zirconia, a synthetic. It comes in blue, colorless, red, orange, yellow, brown and green, and Jewelers of America lists the blue form for December. Hardness spans 6–7.5, but the stone abrades easily. Sri Lanka, Australia, Myanmar, Vietnam and Cambodia are notable sources. Some heat-treated stones can revert in color after long exposure to bright light.
December's stones all prefer a gentle routine. None should go in an ultrasonic or steam cleaner; warm soapy water and a soft brush are enough. Turquoise is porous, so keep it away from heat, acids, cosmetics and skin oils. Tanzanite and zircon both abrade easily, which makes earrings and pendants a better fit than rings worn every day, and tanzanite can crack with sudden temperature changes.
| US list | UK list | Japanese list (2021) |
|---|---|---|
| TurquoiseTanzaniteZircon | Tanzanite(Topaz) | TurquoiseLapis lazuliTanzaniteZircon |
Turquoise. It was December's stone on the 1912 American list, with lapis lazuli as the alternate. Zircon arrived in 1952 and tanzanite in 2002, so Jewelers of America now lists turquoise, tanzanite and blue zircon.
The UK's National Association of Jewellers lists tanzanite as December's main stone and blue topaz as the alternative. Turquoise appeared on an older chart from the National Association of Goldsmiths but is not on the current UK list.
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.