December Birthstone - Tanzanite, Turquoise & Zircon | History, Meaning & Properties

About December's Birthstones

December-born individuals are blessed with not one, but three beautiful birthstones: tanzanite, turquoise, and zircon. While each of these gemstones has its own unique properties and history, they share a predominantly blue color palette that evokes the cool winter month they represent.

Tanzanite, the newest addition to the birthstone calendar, was discovered in 1967 in Tanzania (hence its name). This striking violet-blue gemstone is actually a variety of the mineral zoisite and is known for its remarkable trichroism—appearing blue, purple, or burgundy depending on the viewing angle. Due to its limited source—found only in a small area near Mount Kilimanjaro—tanzanite is considered one of the rarest gemstones in the world.

Turquoise, one of the oldest known gemstones, has been prized for thousands of years across numerous cultures. Its distinctive robin's-egg blue to green-blue color has adorned everything from ancient Egyptian pharaohs' burial masks to Native American jewelry. The name "turquoise" comes from the French phrase "pierre turquoise," meaning "Turkish stone," as the gems were originally brought to Europe through Turkey.

Zircon, often confused with synthetic cubic zirconia despite being a completely different natural gemstone, is one of the earth's oldest minerals, with some crystals dating back over 4 billion years. While zircon occurs in a rainbow of colors, blue zircon—created by heat-treating brown zircon—is the most popular variety and the one traditionally associated with December.

As December birthstones, these three gems are believed to bring wisdom, success, and protection to those born in this month. They're also associated with various wedding anniversaries: tanzanite for the 24th, turquoise for the 5th and 11th, and zircon for the 4th anniversary.

December Birthstone - Tanzanite, Turquoise & Zircon

December Birthstones Properties

Physical Properties: Tanzanite

Mineral: Zoisite (Ca₂Al₃(SiO₄)₃(OH))
Color: Blue to violet-blue, purple
Hardness: 6-7 on Mohs scale
Transparency: Transparent to translucent
Refractive Index: 1.691-1.700
Crystal System: Orthorhombic
Specific Gravity: 3.35

Physical Properties: Turquoise

Mineral: Hydrated copper aluminum phosphate (CuAl₆(PO₄)₄(OH)₈·4H₂O)
Color: Blue to green-blue
Hardness: 5-6 on Mohs scale
Transparency: Opaque
Refractive Index: 1.61-1.65
Crystal System: Triclinic
Specific Gravity: 2.6-2.8

Physical Properties: Zircon

Mineral: Zirconium silicate (ZrSiO₄)
Color: Blue (for December), but also colorless, yellow, red, green
Hardness: 7.5 on Mohs scale
Transparency: Transparent to translucent
Refractive Index: 1.925-1.984
Crystal System: Tetragonal
Specific Gravity: 3.90-4.73

Symbolic Meaning

Wisdom: All three stones are associated with enhanced mental clarity
Protection: Turquoise has been used as a protective talisman for centuries
Spiritual Growth: Tanzanite is believed to facilitate spiritual awareness
Communication: Turquoise is thought to enhance communication skills
Prosperity: Zircon has historically been associated with prosperity and success
Healing: All three stones have been attributed healing properties

Sources & Origins

Tanzanite Source: Exclusively from the Merelani Hills near Mount Kilimanjaro, Tanzania
Turquoise Sources: United States, Iran, China, Mexico, Egypt, Afghanistan
Zircon Sources: Cambodia, Sri Lanka, Thailand, Australia, Madagascar
Historical Turquoise: Persian (Iranian) turquoise has been prized for centuries
American Turquoise: Southwestern US mines produce distinctive varieties
Formation: Tanzanite in metamorphic rocks; turquoise in arid regions; zircon in igneous rocks

Care & Maintenance

Tanzanite Cleaning: Warm, soapy water and soft brush; avoid ultrasonic
Turquoise Cleaning: Damp, soft cloth only; no chemicals or soaking
Zircon Cleaning: Warm, soapy water and soft brush
Heat Sensitivity: All three stones can be damaged by heat
Chemical Exposure: Turquoise is particularly vulnerable to chemicals and oils
Storage: Store separately to prevent scratching; keep turquoise away from direct sunlight

The Rich History of December's Birthstones

Of December's three birthstones, tanzanite has the shortest history, having been discovered only in 1967 by a Maasai tribesman in northern Tanzania. The vibrant blue-violet crystals quickly caught the attention of Tiffany & Co., who named the gem "tanzanite" and launched a major marketing campaign in 1968, calling it "the most beautiful blue stone discovered in 2,000 years." In 2002, the American Gem Trade Association added tanzanite to the birthstone list for December, making it the first addition since 1912.

Turquoise, by contrast, has one of the longest histories of any gemstone, with artifacts dating back to 5000 BCE. Ancient Egyptians used turquoise extensively in their jewelry and ceremonial objects, including the famous burial mask of Tutankhamun. Native American tribes of the southwestern United States have crafted turquoise into jewelry and ceremonial objects for over 1,000 years, believing the stone brought protection, good fortune, and health. Persian (Iranian) turquoise has been prized for its pure, intense blue color since ancient times, and the trade routes that brought this stone to Europe via Turkey gave the gem its name.

Zircon has been used as a gemstone for over 2,000 years, mentioned in Hindu mythology as early as the 6th century. During the Middle Ages, zircon was believed to promote sleep, bring prosperity, and protect travelers from disease and injury. In Victorian times, blue zircon became particularly popular in English jewelry. Despite its long history and natural beauty, zircon has often been overshadowed by more famous gemstones and confused with the synthetic diamond simulant cubic zirconia, despite being a completely different natural gemstone with its own unique properties.

Today, these three December birthstones continue to be valued for their beauty and significance. Tanzanite's limited supply—with experts estimating that the world's only known deposit may be depleted within a few decades—has made it increasingly precious. Turquoise remains an important cultural symbol in many parts of the world, while zircon is appreciated by gemstone connoisseurs for its brilliance and range of colors.

December Birthstone Varieties

Each of December's birthstones comes in various forms and qualities, offering a range of options for those born in this month:

Tanzanite Color Grades

Tanzanite is graded based on its color saturation and tone. The most valuable tanzanites display a rich, violet-blue color with flashes of purple. Lower grades may appear lighter blue or have a stronger purple or burgundy component. Heat treatment is standard practice for tanzanite, enhancing its blue color by reducing the brown or burgundy tones present in most rough material.

Spider-Web Turquoise

This highly prized variety of turquoise features a network of thin, dark veins (matrix) running through the blue stone, creating a spider-web pattern. The contrast between the bright blue stone and the dark matrix creates a distinctive look that is particularly valued in Native American jewelry. The most famous spider-web turquoise comes from the Number 8 mine in Nevada.

Sleeping Beauty Turquoise

Named after the Sleeping Beauty Mine in Globe, Arizona, this variety is known for its solid, sky-blue color with little to no matrix (veining). Its pure, robin's egg blue color has made it one of the most sought-after types of turquoise, especially since the mine closed in 2012, making genuine Sleeping Beauty turquoise increasingly rare.

Persian (Iranian) Turquoise

For centuries, the finest turquoise came from mines in the Nishapur district of Iran. Persian turquoise is known for its intense, uniform sky-blue color, which is considered the standard against which all other turquoise is judged. Due to its historical significance and distinctive color, Persian turquoise commands premium prices in the market.

Blue Zircon

While natural blue zircon exists, most blue zircon on the market is created by heat-treating brown zircon. This treatment produces a bright, electric-blue color that is highly distinctive. Blue zircon has exceptional brilliance and fire, sometimes rivaling diamond in its sparkle, which has made it a popular gemstone for centuries.

White (Colorless) Zircon

Colorless zircon has been used as a diamond substitute long before modern diamond simulants were created. With its high refractive index and strong dispersion (fire), colorless zircon can display remarkable brilliance. While not as hard as diamond, its natural origin and optical properties make it a beautiful gemstone in its own right.

Fascinating Facts About December's Birthstones

Tanzanite's Rarity

Tanzanite is found in only one place on Earth—a small area near Mount Kilimanjaro in Tanzania. Experts estimate that the chance of finding tanzanite anywhere else is one in a million, making it approximately 1,000 times rarer than diamonds. Some geologists predict the supply may be depleted within the next 20-30 years.

Turquoise and Copper

The distinctive blue color of turquoise comes from copper in its chemical structure. When iron replaces some of the copper, the color shifts toward green. This is why turquoise found near iron deposits often has a greener hue. The distinctive matrix (veining) in turquoise is actually the host rock in which the turquoise formed.

Zircon's Age

Zircon crystals are among the oldest minerals on Earth, with some specimens dated to over 4.4 billion years old—almost as old as the planet itself. These ancient zircons provide scientists with valuable information about the early Earth's conditions and have been crucial in understanding our planet's geological history.

Turquoise Absorption

Turquoise is a highly porous gemstone that can absorb oils and liquids from its environment, including those from the wearer's skin. This is why vintage turquoise jewelry often darkens over time—it has absorbed oils from years of wear. Some cultures believe this absorption creates a special bond between the stone and its owner.

December Birthstones in Jewelry

December's three birthstones offer a variety of options for jewelry, each with its own unique characteristics and considerations:

Tanzanite Jewelry Considerations

Setting Types: With a hardness of 6-7, tanzanite requires protective settings, especially for rings. Bezel settings or prongs that protect the stone's edges are ideal.
Color Enhancement: Most tanzanite on the market has been heat-treated to enhance its blue color, a permanent and accepted practice in the industry.
Metal Pairings: Tanzanite's blue-violet color looks stunning against white metals like platinum and white gold, which enhance its cool tones.
Everyday Wear: Due to its moderate hardness, tanzanite rings are better suited for occasional rather than everyday wear to prevent damage.

Turquoise Jewelry Considerations

Treatments: Much of the turquoise on the market is stabilized with resins to improve durability, as natural turquoise can be quite porous and soft.
Traditional Styles: Turquoise has strong associations with Native American and Southwestern jewelry designs, often set in sterling silver with distinctive metalwork.
Modern Designs: Contemporary designers often pair turquoise with yellow gold for a striking contrast that updates the traditional look of this ancient gemstone.
Care Concerns: Turquoise requires special care as it can absorb oils, chemicals, and moisture, potentially changing its color over time.

Zircon Jewelry Considerations

Brilliance: Zircon has exceptional brilliance and fire, making it particularly effective in cuts that maximize these properties, such as brilliant and step cuts.
Durability: With a hardness of 7.5, zircon is suitable for most jewelry types, though it can be brittle and may chip if struck hard.
Color Options: While blue zircon is traditional for December, the stone comes in many colors, offering versatility for different jewelry designs and personal preferences.
Affordability: Zircon offers excellent value, providing impressive brilliance and beauty at a fraction of the cost of many other gemstones.

Care Tips for December Birthstone Jewelry

Clean tanzanite and zircon with mild soap and warm water using a soft brush; avoid ultrasonic cleaners.
For turquoise, use only a soft, slightly damp cloth for cleaning—never soak it or use chemicals, as these can damage the stone.
Remove all three stones before applying lotions, perfumes, or hairspray, as chemicals can damage them, particularly turquoise.
Store each piece separately to prevent scratching, and keep turquoise away from direct sunlight, which can fade its color over time.
Consider removing tanzanite and turquoise jewelry during activities that might subject them to hard impacts or abrasion.

Explore Other Birthstones

December Birthstone - Tanzanite, Turquoise & Zircon

About December's Birthstones