December Birthstone: Tanzanite, and the Genuine Blues Beside It

Ask around and you'll get three answers for December: turquoise, tanzanite, zircon. Our own birthstone series settles it. The Tanzanite Solitaire Earrings carry December on the product itself, so tanzanite leads here. Blue topaz sits beside it as the genuine stone option, and turquoise gets a mention because we stock it and people ask.

The colour that sets tanzanite apart

Most blue stones are just blue. Tanzanite isn't. Turn it in the light and it shifts between violet and blue in the same stone, which separates it from blue topaz, a clean and even blue however you angle it, and from turquoise, which doesn't shift at all: flat, opaque, closer to stone than gem. If December has a signature colour, this violet-blue is closer to it than plain blue.

Birthstone traditions like this one come from custom passed down over generations, not from anything we'd claim a stone does for the wearer. We mention it here as heritage, nothing more.

What our tanzanite pieces are actually set in

Here's the part we won't dress up. The Tanzanite Solitaire Earrings, Tanzanite Birthstone Stud & Pendant Set, Tanzanite Gemstone Pendant, Birthstone Necklace, and Tanzanite Solitaire Stud Earrings for Men are set in 5A+ American Diamond, cut and finished in tanzanite's violet-blue, not the natural stone. Natural tanzanite comes from one deposit on earth and is priced for it, and rarely turns up matched stone for stone across a set. American Diamond is cut to a single specification, so the pair actually matches.

Blue topaz, if the real stone matters to you

This is where December's genuine stone sits in our range. The Blue Topaz Heart Birthstone Stud Earrings, Blue Topaz Gemstone Pendant Set, and Blue Topaz Mineral Stud Earrings for Men are natural blue topaz, not American Diamond, worth knowing if a genuine gemstone is the point. The Silver Ring for Women | Blue Topaz Martini Adjustable is the one to reach for if sizing is a worry, since every HighSpark ring is free-size.

Turquoise, for the rougher option

Turquoise isn't part of our birthstone series, but it's a traditional December stone and we carry it: the Rough Cut Turquoise Pendant, Turquoise Blue Stone Ring, and Turquoise Rough Cut Hoop Earrings. It looks unpolished on purpose, closer to how it comes out of the ground than a cut stone. Worth knowing before you buy it: turquoise is porous and softer than most stones we set, and takes on oils, perfume and lotion over time. Put it on last, take it off first, and skip the usual silver clean.

The silver underneath

Tanzanite, topaz or turquoise, the setting underneath is genuine 925 sterling silver, stamped and finished with our R-Coat™ anti-tarnish coating. The silver is tested by the Sheffield Assay Office (UK) for what it releases against skin under prolonged contact, and comes back nickel-free, cadmium-free and lead-free.

Our full birthstone collection covers the other eleven months, and if a genuine stone is what you're after rather than American Diamond, natural gemstone jewellery runs well beyond December. Rings set in tanzanite, topaz or turquoise sit in the gemstone rings range. For what each month is set in, our birthstones by month guide has the full list, and if sizing decides a ring for you, why free-size solves gifting is worth reading first.