December birthstone: turquoise, zircon and tanzanite

One month, several stones: the list that has changed the most

December is probably the month whose list has changed the most. In 1912, American jewellers retained turquoise and lapis lazuli. In 1952, lapis was replaced by zircon. In 2002, tanzanite, discovered only in 1967, was added. The British list retains tanzanite and turquoise. The older list gave bloodstone and ruby.

If you were born in December, you therefore have a choice: an ancient stone, a brilliant stone or a recent one.

Turquoise: the “Turkish” stone

Turquoise is a hydrated copper aluminium phosphate, sky blue to green, often crossed by brown or black veinlets known as the matrix. Its hardness is 5 to 6, and it is porous. Its name, traced to “Turkish stone”, comes from the fact that it reached Europe through Turkey, from Iran (the Nishapur region). It is also mined in Sinai, the southwestern United States, Tibet and China. It has been used for millennia, notably in Egypt, in Persia and by the Indigenous peoples of North America.

Zircon and tanzanite

Zircon. Zircon is a zirconium silicate of great brilliance, with a hardness of 6.5 to 7.5. It occurs colourless, blue, yellow, orange and reddish brown (the older “hyacinth”). The oldest zircons in the world, found in Australia, are more than four billion years old, which makes them among the oldest known terrestrial materials. Do not confuse it with cubic zirconia, an unrelated laboratory crystal used to imitate diamond.

Tanzanite. It is a blue-violet variety of zoisite, with a hardness of 6.5 to 7. It was discovered in 1967 in the Merelani Hills of Tanzania, and this single major deposit supplies it. Tiffany & Co. gave it its trade name shortly afterwards. It is trichroic: it shows three colours (blue, violet, sometimes reddish brown) depending on the angle. Almost all tanzanites are heated to obtain the blue.

Traditional symbolism

Turquoise has been worn since very early times as a stone of protection in several cultures, notably in the East and among the Indigenous peoples of North America: this is a cultural belief, which we report with respect, not a fact. It is associated with friendship, travel and communication, and with the throat chakra. Zircon, very brilliant, evokes light; tanzanite, a recent stone, has no ancient tradition: it is mainly linked to the third-eye chakra in modern chakra systems. These are symbols, with no scientific proof.

A little history: when lists follow the market

The addition of tanzanite in 2002 by the American coloured gemstone trade association clearly shows the role of commerce in these lists: the stone was not even forty years old, but active promotion and an appealing blue made it popular. Likewise, zircon replaced lapis in 1952, by decision of the American jewellery industry.

This does not make these stones any less beautiful, but it invites us to take a more relative view of the notion of an “authentic” birthstone. The oldest in common use is turquoise, which already appears in the older June and July lists.

Other possible stones in December

• the lapis lazuli, a stone from the 1912 list;
• the heliotrope (bloodstone) and the ruby, from the older list;
• the amazonite and the larimar, in a blue-green close to that of turquoise;
• the zoisite in forms other than tanzanite.

Giving a December birthstone

Turquoise is a warm gift: a bracelet, a necklace or a ring, in stabilised stone if you want a durable piece. A colourless or blue zircon offers a lot of sparkle for a small price. Tanzanite is a rarer gift; a small stone in a pendant is less exposed to knocks than in a ring.

Browse our jewellery, bracelets and gift ideas collections.

Care, treatments and imitations

Turquoise. Porous, it absorbs oils, sweat, perfumes, creams and household products, which can darken it or turn it green. No prolonged soaking, no ultrasonic cleaning, no long exposure to sunlight. Wipe it with a soft, dry cloth, and put it on last.

Turquoise treatments. Nearly all turquoise on the market is stabilised (impregnated with resin to harden it), sometimes dyed, or reconstituted (turquoise powder bound with resin). These practices are common and acceptable provided they are disclosed. The most common imitations are howlite or magnesite dyed blue (“turquenite”), glass and plastic. See howlite and our guide to choosing and caring for your stones.

Zircon. Brilliant but brittle at the edges: avoid knocks. Some colours obtained by heating may fade in strong light.

Tanzanite. Cleavage in one direction: no ultrasonic cleaning or steam, and no knocks. It is almost always heated; imitations exist in glass and laboratory crystals.

Frequently asked questions

Also read

The meanings mentioned belong to tradition and symbolism. They are neither promises of results nor medical advice. Back to Guide to birthstones.