December Birthstones May 3, 2021 – Posted in: Jewelry Blog

Those born in December are lucky enough to claim four birthstones for their month. Zircon, turquoise, tanzanite, and blue topaz are all December Birthstones. All four stones feature different looks and qualities, from the vibrant blues of turquoise and tanzanite to zircon’s wide range of hues.

We have added Blue Topaz to our list. Keep reading to learn more about the Blue Topaz controversy.

What are the Birthstones for December?

The Four December Birthstones Tanzanite Turquoise Zircon and Blue Topaz

There are four Birthstones for the month of December:

  1. Zircon
  2. Turquoise
  3. Tanzanite
  4. Blue Topaz (disputed)

Birthstones have long been a staple gift and accessory associated with each month of the year. Their existence dates back to Earth’s early years. Meanwhile, the original idea of birthstones may trace back as early as biblical times. Some say their origins lie within the Bible, which details the special garments made for Aharon, the High Priest of the Jews. His breastplate contained 12 gemstones, one for each tribe of Israel.

Throughout the years, cultures have disagreed over the months that each birthstone corresponds to. This is why you will find that they have changed over time.

Over the past 50 years, an overall consensus has emerged and most will agree to the birthstone calendar.

December happens to have one of the most famous birthstone months. It may be because a lot of shopping occurs during December or it might be because of the fascinating stones that showcase that month.

View our entire collection of Birthstone Rings and read all of our birthstone articles.

1. December Birthstone: Zircon

The Zircon is the most notable and famous among the December Birthstones. Many people don’t even know that there are even other December Birthstones to pick from.

History of Zircon

Small Loose Raw Zircon Stones Uncut Birth stones

Unbelievably, zircon is the oldest material on Earth. The oldest fragment of zircon, found in Australia, formed at a very early stage of our planet. Zircon Mines are in Burma, Brazil, Cambodia, Korea, Madagascar, Mozambique, Nigeria, Sri Lanka, Tanzania, Thailand, and Vietnam.

Zircon became a December birthstone in 1952, approved by the Jewelry Industry Council of America. Until then, the turquoise and the lapis lazuli were the designated December birthstones. Zircon (or Blue Topaz) is also the 4th wedding anniversary stone.

Myths about Zircon and December Birthstones

Deep Blue Zircon Stone Round Cut December Birthstones

The folklore surrounding the oldest of the December birthstones developed in the middle ages when the gem began appearing in various religious writings. There are those who believe that the stone protects its owner from harm, death, and poison.

Where Does Zircon Come From?

December Birthstone Ring in Box from Estate Diamond Jewelry

Zircon forms naturally. How it forms is still quite a mystery, as it occurs so deep below the ground.

After studying other planets such as the moon, Mars, and Mercury, as well as conducting numerous “what if” studies, most scientists will agree that zircon is formed as a result of tectonic plates colliding. In addition, Earth’s atmosphere was harsh in the early years, contributing to the formation of zircon.

It is important to not confuse Zircon with Cubic Zirconia, the diamond simulant. There is no connection between the two. One, Zircon the December Birthstone, is a natural and genuine stone, while the other is a synthetic simulant.

Different Colors of Zircon

Many Colors of Pear-Shape Zircon on Table

Zircon comes in many colors, which vary based on the conditions during formation. In its purest form zircon will appear colorless. Blue is by far the most popular color of zircon, especially as a December birthstone. This makes the Cambodian and Burmese Mines the major contributors to the market.

Most zircon is naturally red or brown in color, and only after heat treatment, turns a vibrant blue. Other colors may also be heat treated for color improvement, however red and brown turn the blue that we know today as December’s birthstone.

High quality blue zircon will look very similar to Aquamarine (which is the Birthstone for the month of March).

Physical Properties of Zircon

A Loose Polished and Cut Oval Cut Zircon

Another interesting thing about zircon is that its physical properties have a much wider range than most other gemstones. For example, specimens of zircon may range anywhere from 6.5 to 7.5 on the Mohs Hardness Scale. The stone is about as durable as steel. Materials that rate higher on the scale, such as diamonds, can still damage it.

As far as appearance is concerned, zircon has a high refractive index, dispersion rating, and strong pleochroism. This means the stone reflects light well, exhibits fire and brilliance similar to a fine diamond. It is known to change colors at different angles of viewing. For these reasons, the stone can fetch a high price, when compared to other semi-precious gems.

Zircon In Jewelry

December Blue Topaz White Gold Ring with Diamonds on Wood Surface
Blue Topaz is the disputed birthstone for December. Click here to learn more about this Blue Topaz Ring.

Zircon, like the other popular blue-colored stones, really pops in jewelry. It pairs with almost everything and is a real crowd-pleaser.

Those who are purchasing Zircon as a birthstone for a friend usually pick the following pieces of jewelry:

  • Rings (Most Popular)
  • Earrings
  • Pendants

Shapes and Cuts of Zircon

Zircon Round Cut for Dec Birthstone Ring

Because zircon may appear different colors at different angles, the stones must be cut with great care.

Colorless zircon is often a brilliant-cut, while colored zircon is often emerald step cut. Round zircon stones are usually given a zircon cut, which is a standard round brilliant cut with an extra row of facets at the edges.

Common shapes of zircon are Oval Cut, Round Cut, Pear Cut, Emerald Cut, and Trillion Cut.

Clarity & Color of Zircon

Blue Zircon Pear Shape Loose but High Quality Unmounted

Zircon is generally both transparent and translucent. It has a brilliant, vitreous sheen when polished.

Some zircon may contain radioactive elements, thorium, and uranium, which cause the crystal structure to break down over time. These stones will be near-amorphous and appear low luster and low green in color.

These very rare forms of radioactive zircon are not dangerous, and in fact, are very desirable to jewelers and collectors. Zircon stones with cat’s eye chatoyancy are also a rarity. The impurities in the stone cause different colors.

Carat Size of Zircon

Different Sizes of Square Cut Blue Zircon

The size and weight of colored stones are often unrelated. For that reason, colored gemstones should be purchased based on size and dimensions, not carat weight.

What does this mean?

With diamonds, the price is judged by placing the diamond on a scale and measuring it exactly to at least the second decimal point of carats (for example 1.87-carats).

With Zircon and many other semi-precious stones, the price is evaluated by size. So, for example, you would ask for a 20mm x 20mm round cut zircon. The actual weight usually won’t matter.

Picking the Right Zircon For You

Shopping for Zircon at Estate Diamond Jewelry with Credit Card

Zircon has good hardness, but it may be too brittle for fully open settings. It is best to wear it in a bezel setting or only as occasional jewelry. Because the gem is very dense, it is usually small in most jewelry. The larger stones are heavy. Wear them on sturdy brooches or thick chains.

Most often, blue zircon is worn in earrings and rings as a December birthstone jewelry piece. Colorless zircon is often worn on bridal jewelry as a high-quality diamond substitute. Luckily, zircon comes in many colors and is therefore extremely versatile.

Cleaning Your December Stone

Cleaning Zircon and December Birthstone with Soap and Brush

Zircon is fairly easy to care for. It is durable, but care must still be given as it can still be damaged. Remove it when cleaning, gardening, or completing any other hazardous tasks. Zircon is also sensitive to ultraviolet and sunlight. Don’t wear it outside for long stretches of time.

To clean the stone, gently soak in warm water and wash with mild soap. You can also use a very soft brush to help clean the gunk. Pat to dry. Although you might only wear your zircon jewelry in December, you should still clean your fine birthstone jewelry frequently.

2. December Birthstone: Turquoise

Although the turquoise may not be the most famous among the December Birthstones, it is the most beloved by devoted birthstone enthusiasts. Its complexity and uniqueness give it a cult-like following among those that know a lot about it, making the turquoise one of the most mystifying birthstones of the year.

Antique Persian Turquoise Brooch, set in gold and adorned with diamonds
A rare turquoise brooch from our vintage brooch collection

History of Turquoise

Turquoise is the second oldest December birthstone. It is also the 11th wedding anniversary stone. Ancient Cultures considered Turquoise to be a holy stone, and it often adorned royal figures and leaders.

Turquoise did not become one of December’s birthstones until 1912 when the American National Association of Jewelers replaced bloodstone and ruby with turquoise and lapis lazuli.

Myths About Turquoise

Sterle Turquoise Brooch from Estate Diamond Jewelry
A rare Sterle Turquoise Brooch from our collection, adorned with gold and diamonds

In most cultures, turquoise was believed to hold protective powers. The stone was often placed on weapons, crowns, jewelry, and buildings. In Native American culture, it was also carved into shapes, which were used as family heirlooms and in rituals.

In addition to protection, the stone was also said to cultivate happiness, health, and harmony. For that reason, turquoise was often gifted to those getting married or celebrating a birthday. The gem was considered anti-inflammatory and detoxifying. Turquoise was used to fight viral infections and ward off depression and anxiety in ancient cultures.

Where Does Turquoise Come From?

Blue Turquoise Mine in Rocks

Mining for turquoise commonly occurs in the Southwest United States. These turquoise mines, opened by the Anasazi in 1000 AD, are a famous tourist location. Other common areas of occurrence include Mexico, Iran, Serabit el-Khadim in the Sinai Peninsula, Egypt, and Israel.

The name turquoise is fairly new. It is a French word meaning “stone from Turkey” that was created in the thirteenth century. The gem was brought over from Turkey to Western Europe during that time.

Turquoise forms when water containing copper and aluminum seeps through rocks. The gem forms in veins inside the rock. Eventually, if enough veins form in one rock at once, they become a clump of turquoise.

The stone receives a polish and/or slice after it’s mined. Naturally, turquoise appears waxy and porous. In order to enhance its appearance and increase stability, the stone is often treated with plastic lubricants and dyes.

Physical Properties of Turquoise

Bulgari Turquoise Ring

Turquoise containing high levels of copper usually appears a lot bluer. Stones with high iron levels appear greener. Less common is turquoise that contains high levels of zinc. In these cases, the gem will appear more yellow.

The matrix, a thin, intricate vein-like pattern throughout the gemstone is usually the easy way to identify the stone. It runs through the stone and resembles cracks in the ground. Some jewelers and collectors consider these veins what make the stone so unique and valuable, while others consider them blemishes that decrease the stone’s value.

Turquoise is on the low end of the Mohs Hardness Scale, scoring a 5-6 on average. Some variations of the gem can score as low as a 3. In other words, it is easy to scratch or break turquoise.

Turquoise In Jewelry

Onyx and Turquiose Necklace
A rare Art Deco Turquoise bracelet from our collection

The 4Cs don’t judge turquoise. The physical properties of the stone vary too greatly. Instead, the color, matrix, hardness, and size determine the value of turquoise.

The bright robin’s egg blue Turquoise is considered most valuable. In this shade of blue, it is considered most desirable. Other color variations, such as green or yellow, will negatively impact the value of the stone.

There are some places that place value on the turquoise matrix. The matrix lowers the value of the stone in America. Traditional Native American jewelry celebrates the natural veins and webs that appear in the gem.

Conditions during formation vary, and turquoise may be anywhere from fragile to durable. Turquoise with a high Mohs Scale rating and solid durability is considered the more valuable. The higher the rating, the more long-lasting the stone will be.

How to Shop for Turquoise December Jewelry?

Holding an Vintage Bulgari VCA Cocktail Ring
Rare Bulgari Turquoise Cocktail Ring. Click here to view more.

Just like its sister December birthstones, turquoise is also priced by size not carat weight. Additionally, color plays a major role in pricing this gemstone. You should always look into the different variants of turquoise to determine which one you like best.

The Turquoise Quality Index is used by many to determine the stone’s quality. This is a scale between 8 and 100 that considers eight factors within two categories. Each factor is weighted according to importance. The higher the total score, the more valuable the stone.

Category one, structure, is composed of hardness, enhancement, composition, and cut. Together, this category is worth up to 55 points. The second category, rarity, rates a stone’s availability, color, matrix, and contiguous size. This category is worth up to 45 points.

If you are looking for a particular turquoise gem or turquoise jewelry, feel free to reach out to ask.

Caring for and cleaning Turquoise

Cleaning Turquoise December Necklace with toothbrush and soap

Turquoise is very delicate. Use the same technique as when cleaning most other jewelry, but just make sure to use a lot more care. Soak it in warm water and gently wash it with mild soap. You can use a very soft toothbrush if there is any larger or stickier gunk or dirt.

Wash and wear turquoise with care. Many of them have dye and plastic treatments. They will deteriorate if exposed to steam, heat, or other chemical solvents. You should never clean turquoise with an ultrasonic cleaner.

You should avoid exposing turquoise to chemicals, cosmetics, heat, and even natural skin oils. These will likely change the color of the stone.

3. December Birthstone: Tanzanite

December Birthstones Tanzanite Ring surrounded a double halo of round diamonds

Tanzanite is a stunning stone, and by now almost as famous as Zircon. It is one of the most desired semi-precious stones on the market and its rich and deep color is one of the most recognizable.

History of Tanzanite

raw tanzanite stones showing different saturations and shades of blue

Tanzanite is December’s newest birthstone. Its discovery is very recent. The first eruption of Mount Kilimanjaro formed the stones.

Tanzanite didn’t become one of Decembers birthstones until 2002. The American Gem Trade Association named it the third birthstone alongside zircon and turquoise. It is also the 24th wedding anniversary stone.

Myths about Tanzanite

Tanzanite and Diamond Halo Ring, set in platinum

Tanzanite comes only from Tanzania, and because we have only known about the stone’s existence for about 50 years, folklore and legends have not yet developed.

Where Does Tanzanite Come From?

Exploring Tanzanite Mines

As mentioned earlier, Tanzanite is particularly unique in that it only forms in Tanzania. All the Tanzanite in the world all comes from Tanzania.

In 1967, a giant fire scorched most of the grass and earth surrounding Mount Kilimanjaro, revealing the rare stones. They turned a bright blue-violet, making them easy to spot.

Maasai herders who were tending to their livestock first found the stones. After notifying prospector Manuel d’Souza, the government quickly approved permits to begin mining. They initially thought they were mining sapphire but soon realized it was a never-before-seen variation of zoisite.

The local government mined more than 2 million carats of tanzanite before it began regulation. In 2012, an independent study found that just one of the four tanzanite mining blocks will be depleted in about 30 years at current production rates.

Colors of Tanzanite

Tanzanite Ring with double Halo of Diamonds. Curated by Estate Diamond Jewelry

Retail Tanzanite appears violet-blue in color. Occasionally it will feature natural burgundy or brown hues. Often the heat-treatment for Tanzanite will occur within the earth. Other stones will require heat treatment to improve their desirability.

December’s youngest birthstone does not follow the same process as other heat-treated gems. Most stones require 1,000 degrees Fahrenheit for several days. Tanzanite needs around 600 degrees for less than one hour.

There are very rare tanzanite stones that will not require any treatment at all.

Physical Properties of Tanzanite

Tanzanite lands at about 6.5 on the Mohs Hardness Scale. It is fairly durable but is still susceptible to surface damage if dropped or scratched.

The stone naturally ranges from blues to violets. This makes them great alternatives to sapphires, aquamarines, and blue topaz. Tanzanite has strong pleochroism, meaning it reflects different colors at different angles. It is also dichromatic, meaning it absorbs rays of light in different amounts.

Tanzanite In Jewelry

Tanzanite and Diamond Necklace

Tiffany & Co. Introduced the World to Tanzanite.

In 1968, Tiffany became the official international distributor of Tanzanite, this occurring just one year after the first gemstone was found.

Soon after, the company began releasing exclusive pieces of fine tanzanite jewelry. The publicity campaign was effective. They coined the phrase, “Tanzanite can only be found in two places, Tanzania and Tiffany’s.”

Click our link to view our December Birthstone Jewelry.

The Four C’s of Tanzanite

Tanzanite and Diamond Ring

Tanzanite is most valuable when it appears a deeply saturated blue-violet. Paler variations are more inexpensive.

Cutting a Tanzanite properly is of utmost importance. A poorly cut stone will not let the light do justice to the color. Bluer stones are more valuable, so lapidaries will often make precise cuts that reflect this color more.

Tanzanite rarely has visible inclusions, so when they do occur it lowers the value significantly. The bluest stones are normally over 5 carats. Smaller stones are often less vibrant in color.

Picking the Right Tanzanite For You

Tanzanite is available in limited quantities. It is also growing in popularity. It is a very rare jewel. And because it only forms on a small stretch of land in Tanzania, the stone’s price and availability are entirely dependent on what happens there.

It is important to know how to safely set tanzanite. We recommend wearing the stone in a necklace or earring (as opposed to a ring), for less exposure to wear and tear. However, if you choose to purchase a ring, simply ensure that your stone is in a protective setting.

Smaller stones are usually bluer and therefore more valuable. Keep this in mind as you select your gem.

Cleaning Tanzanite

This December birthstone is generally safe for everyday wear but should be removed for strenuous activity or when you are using chemicals of any kind. Tanzanite has good color stability and will not change under normal light exposure or in normal temperatures.

Like with most stones, regularly cleaning is necessary to keeping your tanzanite looking its best. Gently wash with warm water and mild soap.

Is the Blue Topaz one of the December Birthstones?

Blue Topaz Gold Ring
Blue Topaz is also the birthstone of December. Click here to purchase this ring.

Most authorities say that there are only 3 birthstones in December: Zircon, Turquoise, and Tanzanite. Some authorities insist that there are actually 4 birthstones: Zircon, Turquoise, Tanzanite, and Blue Topaz.

We have over 40 years of experience in the jewelry industry. We’ve watched the birthstone trend evolve and grow over the years. Unlike most experts, we have no problem adding another stone to the month of December. Why not?

Birthstones should follow the hearts of the people. They added the Blue Topaz to the list, and we agree that it belongs there! The entire list is arbitrary and therefore adding another ring to the mix only adds to the fun and excitement.

Final Thoughts on December Birthstones

We always recommend feeling confident when purchasing. Whether you’re gifting a stunning December birthstone to your favorite birthday girl or congratulating a couple on a special wedding anniversary. Even if you’re simply investing in some December jewelry for yourself.

We hope this guide helps you better understand the four beautiful December birthstones.

Gift a December birthstone this winter!

Learn about the Other Birthstones

Birthstones Gemstones

Each month has a fascinating birthstone (or birthstones) associated with it. Click the links below to learn more about each month.