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What Is the December Birthstone? Turquoise, Tanzanite and Zircon

By Digital Towns Crystals ยท Last reviewed October 6, 2026

Short answer: December has three birthstones: turquoise, tanzanite and zircon. All three are blue. Turquoise is an opaque sky blue to green stone, often with dark veins, prized for thousands of years. Tanzanite is a violet-blue gem mined commercially in only one place, in Tanzania. Zircon is a brilliant natural gem, often blue, and not the same as cubic zirconia.

Why does December have three birthstones?

The 1912 list adopted in the United States gave December turquoise and lapis lazuli. In 1952, lapis lazuli was replaced with zircon. In 2002, tanzanite was added as a December birthstone. Some lists, including GIA's, also give blue topaz as a December stone.

Turquoise

What is turquoise?

Turquoise is a hydrated phosphate of copper and aluminum. It is opaque, ranges from sky blue to green, and often carries veins of matrix, remnants of the rock it formed in, which can be brown, black or golden. A fine web of dark veins is called spiderweb matrix. Turquoise rates 5 to 6 on the Mohs scale, and it can be discolored by chemicals, cosmetics and even skin oils.

Where does turquoise come from?

Turquoise has been mined in the Nishapur district of Iran for more than a thousand years. The even, intense blue from there gave the trade the terms "robin's egg blue", "sky blue" and "Persian blue", now used for turquoise of that color from anywhere.

New Mexico was the largest producer in the United States until the 1920s. Today most US production comes from Arizona and Nevada, from mines with names like Dry Creek, Easter Blue and Fox. Arizona's Kingman mine is a historically important source of intense blue turquoise, and the Sleeping Beauty mine, now closed to turquoise mining, was a prolific producer for more than four decades. Today China is the world's largest producer, mostly from Hubei Province.

What is turquoise traditionally associated with?

Turquoise has been treasured for millennia. The rulers of ancient Egypt wore it, and it adorns the funerary mask of King Tutankhamun. Chinese artisans carved it more than 3,000 years ago. From the 1200s, Europeans believed it protected the wearer from falls, especially from horses. It holds deep meaning for many Native American peoples of the Southwest: the Pueblo held that turquoise got its color from the sky, and the Apache believed it could be found by following a rainbow to its end. In Tibet it is considered a national treasure and is believed to bring good fortune and protection. In European tradition, a turquoise ring means "forget me not". It is the gem of the eleventh wedding anniversary.

Turquoise treatments and imitations

Much turquoise is treated. Soft, chalky material is often stabilized, impregnated with epoxy or acrylic resin to harden it and improve its color and polish. Some turquoise is dyed, and some cavities are filled with metal-loaded epoxy to imitate pyrite. The most common imitations are dyed howlite and dyed magnesite, white stones that take dye well; howlite even has natural dark veins. Stabilized turquoise is genuine; it should simply be described as treated.

Tanzanite

What is tanzanite?

Tanzanite is the blue to violet variety of the mineral zoisite. Its color ranges from pure rich blue to violet, with blue considered most valuable, and it often shows different colors from different directions. It rates 6 to 7 on the Mohs scale.

Where does tanzanite come from?

Blue zoisite from Tanzania was identified in 1962, and in 1967 prospectors found its main source, the Merelani Hills in northern Tanzania, in sight of Mount Kilimanjaro. It is still the only place on Earth where tanzanite is mined commercially.

Tiffany & Co. gave the gem its name, after its country of origin, and launched it with a major advertising campaign in 1968. It is the gem of the twenty-fourth wedding anniversary.

Is tanzanite heat treated?

Most tanzanite starts as brownish zoisite and is heated to bring out the blue to violet color. The result is permanent, and it causes no durability problems.

Zircon

What is zircon?

Zircon is a natural mineral, zirconium silicate. Colorless zircon is known for its brilliance and fire, flashes of multicolored light, which led to centuries of confusion with diamond. It comes in red, orange, yellow, brown, green and blue, and blue is the most popular December color. It rates 6 to 7.5 on the Mohs scale.

Zircon is not cubic zirconia. Cubic zirconia is a man-made material that imitates diamond. Zircon is a genuine gem mineral, and one of the oldest on Earth: zircon grains from the Jack Hills of Western Australia have been dated to about 4.4 billion years old.

Where does zircon come from?

Sri Lanka is a major source, especially the Elahera region. Australia's Harts Range produces zircon in yellow-brown, orange-brown, pink and purple. Zircon is often found near sapphire, and both are mined in Myanmar, Vietnam and Cambodia.

What is zircon traditionally associated with?

Some scholars trace the name to the Arabic zarkun, "cinnabar" or "vermilion", others to the Persian zargun, "gold colored". In the Middle Ages, zircon was thought to scare off evil spirits. In Hindu tradition, zircon alternates with hessonite garnet as one of the nine gems of the navaratna. The Victorians were fond of blue zircon, and fine stones appear in English estate jewelry from the 1880s.

Is blue zircon natural?

Most blue and colorless zircon is heat treated, usually from light brown material. Some heat-treated stones can slowly revert toward their original color after long exposure to bright light.

Which December birthstone should you choose?

Turquoise Tanzanite Zircon
Look Opaque sky blue to green, often veined Transparent violet-blue Transparent, very brilliant, often blue
Hardness (Mohs) 5 to 6 6 to 7 6 to 7.5
Best for Pendants, cabochon rings, bracelets Earrings, pendants, protected rings Rings and earrings, with care for edges
Common treatment Stabilizing, dyeing Heating Heating

How do you care for December birthstones?

  • Turquoise: clean with warm, soapy water. Never use steam or ultrasonic cleaners. Keep it away from high heat, acids, cosmetics and perfume, and wipe off skin oils, which can discolor it over time.
  • Tanzanite: clean with warm, soapy water. It resists normal heat, light and common chemicals but can crack with very high heat or sudden temperature changes, and it abrades easily. It suits earrings and pendants best; in a ring, use a protective setting.
  • Zircon: clean with a soft brush and mild soap in warm water. Do not use ultrasonic or steam cleaners. Zircon tends to abrade, so avoid wearing it for rough work such as gardening, sports or washing dishes, store it apart from other jewelry, and keep heat-treated stones out of prolonged bright light.

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Frequently asked questions

What is the December birthstone color?

Blue. Turquoise is sky blue to green, tanzanite is violet-blue and zircon is most often sold in blue. Some lists also include blue topaz for December.

Is zircon the same as cubic zirconia?

No. Zircon is a natural mineral, zirconium silicate, and one of the oldest minerals on Earth. Cubic zirconia is a man-made material created to imitate diamond.

Why is tanzanite found in only one place?

It formed under an unusual combination of geological conditions in the Merelani Hills of northern Tanzania, the only place where it is mined commercially. That single source is part of its appeal.

How can you tell if turquoise is real?

Look for natural variation in color and matrix. Very uniform color, dye collected in cracks and an unusually low price can point to dyed howlite or magnesite. Stabilized turquoise is real turquoise that has been treated, and a good seller says so.

Which December birthstone is most durable?

Zircon and tanzanite are harder than turquoise, but both abrade easily, so their facets can wear with rough use. For everyday wear, a protective setting helps with any of the three.

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