December Birthstones: Tanzanite, Zircon and Turquoise
December has three official birthstones: tanzanite, zircon and turquoise. Every one counts, so you can choose by color, hardness or taste. Each is described below.
Tanzanite, a December birthstone
| Color | Blue to violet |
|---|---|
| Mineral | Zoisite |
| Hardness | 6 to 7 on the Mohs scale (diamond is 10) |
| Main sources | Tanzania (the Merelani Hills, the only commercial source) |
| Anniversary gem | 24th wedding anniversary |
Tanzanite treatments
- Most tanzanite starts as brownish zoisite that is heated to bring out its blue to violet color.
Is tanzanite good for everyday wear?
GIA suggests tanzanite for earrings and pendants. It is not recommended for a ring worn every day, though in a protective setting it makes a good ring for special occasions.
Tanzanite history
- Its main source in the Merelani Hills was found in 1967.
- Tiffany & Co. became its main distributor and launched it with an advertising campaign in 1968.
How to clean tanzanite
- Warm, soapy water and a soft brush: always safe.
- Ultrasonic cleaner: not recommended.
- Steam cleaner: not recommended.
It can crack in very high heat or sudden temperature changes. Clean with warm, soapy water.
Zircon, a December birthstone
| Color | Blue, colorless and other colors |
|---|---|
| Mineral | Zircon |
| Hardness | 6 to 7.5 on the Mohs scale (diamond is 10) |
| Main sources | Sri Lanka, Australia, Cambodia, Myanmar |
Zircon treatments
- Zircon is commonly heated to produce its blue and colorless varieties, as well as orange, yellow and red.
Is zircon good for everyday wear?
Zircon tends to wear along its facet edges, so take it off for gardening, sports or washing dishes.
Zircon history
- Colorless zircon sparkles with flashes of color, which led to centuries of confusion with diamond.
- Victorians loved blue zircon; fine examples appear in English estate jewelry of the 1880s.
How to clean zircon
- Warm, soapy water and a soft brush: always safe.
- Ultrasonic cleaner: not recommended.
- Steam cleaner: not recommended.
Heat can change the color of some zircon. Use a soft brush, mild soap and warm water.
Turquoise, a December birthstone
| Color | Blue to green |
|---|---|
| Mineral | Turquoise |
| Hardness | 5 to 6 on the Mohs scale (diamond is 10) |
| Main sources | Iran, United States (New Mexico, Arizona, Nevada), China |
| Anniversary gem | 11th wedding anniversary |
Turquoise treatments
- Some turquoise is treated to make it more durable: it may be dyed, or filled with epoxy or acrylic resin for greater hardness or better color.
Turquoise history
- It decorates the funeral mask of King Tutankhamun, made more than 3,000 years ago.
- Turquoise has been mined in the Nishapur district of Iran for more than 1,000 years.
How to clean turquoise
- Warm, soapy water and a soft brush: always safe.
- Ultrasonic cleaner: not recommended.
- Steam cleaner: not recommended.
High heat can discolor and break it. Clean with warm, soapy water.
December birthstone and birth flower
December also has two birth flowers: the narcissus and holly, which stand for rebirth, hope and protection. The Birth Flower Finder covers every month.
Buying for someone not born in December? The Birthstone Finder shows every month's stones and colors in one chart. Tanzanite and turquoise are also given for wedding anniversaries; the Anniversary Calculator shows which one is coming up next. If the gift is a surprise, a birthday countdown counts down to the day.
Birthstones for other months
December Birthstones questions
What is the December birthstone?
December has three birthstones: Tanzanite, Zircon and Turquoise. All of them are official, so you can choose the one you like best.
What color is the December birthstone?
Tanzanite: blue to violet. Zircon: blue, colorless and other colors. Turquoise: blue to green.
Which December birthstone is the hardest?
Zircon, at 6 to 7.5 on the Mohs scale. Tanzanite is 6 to 7 and turquoise is 5 to 6.
Is blue topaz a December birthstone?
Not on the official US list, which gives December tanzanite, zircon and turquoise, and gives topaz to November. Some jewelers still sell blue topaz as a December stone. GIA notes that most blue topaz starts out colorless and is turned sky blue by treatment.
Is tanzanite an anniversary gem?
Yes. GIA gives tanzanite for the 24th wedding anniversary.
Why does December have more than one birthstone?
The US list from 1912 has been updated a few times. Zircon was added to December in 1952, and tanzanite in 2002.
Published October 7, 2026. Last updated October 7, 2026.