Blue December Birthstones

Published: Dec 2010
by Jerry Sisk, GG & JTV Co-Founder
from In the Loupe Volume VIII

Just to set the record straight, I am not talking about moods or music. I am talking about birthstones. December has one of the best gemstone line-ups around turquoise, lapis lazuli, blue topaz, blue zircon, and tanzanite. These are the gems that you will find on the modern and traditional birthstone lists here in the US. Of course, many are quick to point out that other lists exist.

If you were to check further, you would probably find mystical birthstones and Ayurvedic gems for each month. Dig a little deeper, and you will find that the choice of birthstones often varies by country. That being said, the five gemstones mentioned above offer a nice range of shades in blue and a nice combination of old and new and by old, I mean ancient.


Consider turquoise. Its natural beauty has captivated a multitude of cultures spanning millennia. Where does thestory begin? That is hard to say, but turquoise has been found in royal burial chambers dating back as far as 5500 BC. It is now 2010, so you can do the math. That is a pretty amazing track record.

Turquoise is available in a range of colors from green to robins egg blue, with or without webbing. Webbing refers to the fine dark lines that are found interlaced throughout the gemstone. This is often seen in Chinese turquoise and can create some visually striking patterns. Turquoise is also a great collectors gem since it is available from a number of sources the US, China, Mexico, Turkey, Brazil, Argentina, Iran, and even Tanzania. The last source is home to another blue birthstone, which brings me to the new tanzanite.



Tanzanite is a relative baby compared to turquoise and lapis lazuli. Discovered around 1967, it remained in near obscurity for many years due to inconsistent supply. It was not until the 1990s that it came into its own. As production became more regular, this rich blue-violet variety of the mineral zoisite became more available to collectors and jewelry manufacturers. With the advent and growth of television shopping networks, this amazingly beautiful gem was seen in tens of millions of homes across North America and became an instant success.

Tanzanite is unusual in that there is only one commercially viable source. (Most gems can be mined in multiple countries and multiple locations within a country.) With this gem, there is only one small strip of land, located at the base of Mount Kilimanjaro in the Merelani Hills of Tanzania. Tanzania itself is a living zoo with a multitude of wild and exotic animals. Kilimanjaro, often cited as the largest freestanding mountain in the world, is actually a massive stratovolcano that is not entirely dormant. All of this serves as the backdrop for one of natures most amazing gemstones. What makes tanzanite so popular? Color is a major consideration. It offers rich, transparent blues to blue-violets that are nothing less than eye candy. It also offers softer pastels for those who prefer a subtler expression of color.

Another very important factor is size. Tanzanite is available in five, ten, or twenty-carat stones... even larger for the serious collector. Compared to fine, gem-quality sapphires and spinels of similar color, it is both reasonably available and more affordable by a significant margin. It also has sufficient durability to make it a favorite in a wide range of jewelry.

Many adjectives have been used to describe the beauty and elegance of tanzanite, yet its history is still fairly unknown to most. Considered a recent addition to the world of gemstones, tanzanite was brought to light in the mid to late 1960s. The question of who first discovered this rare and beautiful gem is still a matter of debate.

Debates aside, one important fact remains: Tanzanite has made a deep and lasting impression on both the gemstone industry and the general public as a whole, but its road to fame and prominence has been rocky, to say the least.

Tanzanite History

Its start was impressive. Brought to the attention of Henry B. Platt, then vice president of Tiffany & Co. in New York, the material was named after its country of origin, Tanzania. Having one of the most famous jewelry companies in the world recognize tanzanite's potential was definitely serendipitous. But, as the supply side was not stable, the marketing and promotion of tanzanite eventually came to a halt, causing tanzanite to fall back into obscurity.

The Tanzanian government, recognizing the potential for tanzanite, intervened in 1971 and made an effort to exploit this national resource. The mining and control of tanzanite was subsequently turned over to the State Mining Corporation around 1976. During this period, the mining and production of tanzanite fell off dramatically, causing tanzanite to lose what little market share it had gained.

By the early 1980s, conditions had not improved, so production could be described as irregular at best. Toward the latter part of the '80s, thousands of illegal miners had flooded into Merelani Hills in Northern Tanzania and started exploiting the resources that were present.

It wasn't until 1991 that the Tanzanian government regained control of this area and started issuing licenses to mine. Most of the licenses went directly to native Tanzanians. Interestingly, one of the largest areas within the limited tanzanite-bearing range, Block C, was licensed to a graphite-mining concern that subsequently went out of business.

Geographically, the 6-kilometer-long area where tanzanite has been found is part of a larger geological formation called the Mozambique Belt (recently renamed the East African Orogon). Nestled at the base of Mount Kilimanjaro in the Merelani foothills of Northern Tanzania, the formation was originally divided into four geographic blocks by the government (six with the addition of the extended A and D blocks).

Tanzanite Formation and Mining

The formation of tanzanite is an amazing process that spans across more than 500 million years and requires a very complex series of geological events to occur. In addition, the proper temperature and elements must be present before crystallization of tanzanite can begin. The main coloring agent, vanadium, is required to produce the rich blue-violet colors that are so highly prized.

Interestingly, tanzanite is found in what geologists call "boudins." A boudin is a sausage-shaped formation that is known to contain tanzanite crystals. However, not every boudin will produce tanzanite, and many that do produce contain such low-grade material that it is not useful for jewelry. Unfortunately, these boudins snake around within the earth, making straight, horizontal shafts impractical for mining.

A bi-product of tanzanite mining is another very beautiful gemstone called tsavorite, a form of grossular garnet. As more tsavorite is found, the likelihood of finding jewelry-grade tanzanite lessens. Rhodolite and kyanite are also associated with tanzanite formations.

Most mining is still performed by individuals under what would be considered primitive conditions. Blocks B and D, still actively in production, contain hundreds of small mining operations. Block C, which has been modernized by an international concern, is the only state-of-the-art facility in the entire mining district. Unfortunately, even with high-tech equipment and analysis, the mining of tanzanite is still a difficult task.

Tanzanite itself is actually a variety of the mineral zoisite. While particularly well known for its blue to violet members, greenish to grayish-green material is also prized and goes by the same name. Although pure green tanzanite does exist, it is extremely rare and commands exceptional prices from collectors.

Tanzanite Care and Treatment

Tanzanite looks very different in rough form. Most pieces are the color of Coke-bottle glass when mined and transform into the rich blues to violets after heat treatment. Yet not every piece will heat to the desired color, and some pieces may require multiple heat treatments to complete the process.

Somewhat softer than quartz, tanzanite may be mounted in any form of jewelry. When it is set in rings, additional care should be taken. Tanzanite should never be subjected to extremes in temperature.

Interestingly, some pieces appear more blue than violet. Since tanzanite is a highly pleochroic gem, the color may be manipulated by cutting the stone on one of two axes. Bluer stones are cut on the shorter axis and generally do not provide as high a yield. Consequently, intense blue tanzanite costs more than its violet siblings.

Tanzanite Popularity

With the advent and growth of television shopping networks, tanzanite has established itself as a major player in the colored-stone market. Sales of tanzanite continue to grow as tens of millions of homes are introduced to this exotic and beautiful gemstone. The proliferation of online shopping has also helped to increase its popularity.

Unfortunately at present, tanzanite is considered a finite resource. Based on historical data and the current mining environment, experts in the field estimate that tanzanite mines have approximately 20 - 30 years left. If no other sources are found, the history of this beautiful and highly prized gemstone may be cut short.

There is still hope that with the emergence of new technologies and additional exploration, other sites may be discovered. If not, then be thankful if you are lucky enough to own one of nature's most beautiful creations.

Lapis Lazuli, Blue Zircon, Blue Topaz

I do not have enough space to talk in depth about the remaining three gemstones, but each has its own special place in the realm of birthstones. Lapis lazuli has a regal feel and look, while blue zircon exhibits incredible sparkle on a bright, sunny day. Sky, Swiss, and London blue topaz offer a continuous palette of colors, ranging from light aquamarine to the more intense blues of sapphire.

Sky Blue Topaz

Sky blue topaz's clear, clean and delicate color is reminiscent of the sky on a cloudless day. Sky blue is a favorite color for those who love light colors and airy spaces which makes this topaz a popular gemstone.

Trade names associated with blue topaz include sky blue, swiss blue and London blue. These names refer to the color range of the gemstone, with sky blue being the lightest in color and London blue the darker color.

Without a doubt, sky blue topaz is one of the most affordable of all gemstones in todays world. Its pleasing, spirit-lifting pastel blue color gives you the look of aquamarine but with a more affordable price tag.

Beginning life as a colorless topaz, sky blue topaz is the result of modern technology meeting Mother Nature. In the 1970s, gem dealers learned that they could treat white topaz by exposing it to radiation and then heat. What was originally a colorless gem then turned the blue of aquamarine.

When blue topaz first appeared on the market, the new innovative gem was sold at rather steep prices. Fortunately, as more dealers figured out how to produce the color, production expanded and prices dropped to their affordable levels today.

One of the birthstones for December, sky blue topaz is said to help with ones concentration. When given as a gift, it symbolizes eternal love. It is also the anniversary gem for the fourth year of marriage.

While Brazil is the chief source for most topaz today, it is also found in Australia, China, Madagascar, Mexico, Burma, Namibia, Nigeria, Pakistan, Sri Lanka, the U.S. and Zimbabwe.

Swiss Blue Topaz

One of the prettiest and most popular in the blue topaz family is Swiss Blue topaz. This is a popular family with three different shades of blue: Sky Blue, Swiss Blue and London Blue topaz.

Sky blue is very much like aquamarine in its color range. London blue is a darker blue tone and Swiss blue is the bright, electric, more vivid blue of the three. Blue topaz in all three colors constitutes one of the most popular of gemstones.

Swiss blue is an intense blue color range that is verily described as vivid, electric or super blue. Some of the most vivid shades of Swiss blue topaz can be compared to the rich colors of the Caribbean Ocean which is very close to the color of top Brazilian Paraíba tourmaline. Its no wonder it is so well liked; it is gorgeous and affordable.

Most Swiss blue topaz starts as white or colorless topaz from either Brazil or Sri Lanka. It is then irradiated to activate the intense, stable color centers that give us that electric, vivid blue color. Topaz is one of the hardest of all gemstones. With a hardness of 8 on the Mohs scale, it takes a superior polish and gives a beautiful luster. Flawless by nature, Swiss blue topaz is natural beauty.

Light or dark, new or old... join us at Jewelry Television as we celebrate the December blues! May the holiday season find you in good health and in the company of friends and family.


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