December Birthstones: Blue Topaz, Blue Zircon, Tanzanite and Turquoise
23 Minute Read
What is December's Birthstone?
Those born in December are lucky to be able to choose from four gorgeous blue gemstones: Blue Topaz, Blue Zircon, Tanzanite and Turquoise.
Blue Topaz
What is the Blue Topaz Birthstone Month?
Blue topaz is one of the modern birthstones for the month of December. Blue topaz is a silicate mineral made up of aluminum and fluorine. It has a glass-like luster and deep cleavage, making it delicate and brittle. Its colors range from dark to cool blues. Depending on the depth of the color, a blue topaz may be known as London Blue (a deep, inky color), Swiss Blue (vibrant light blue) and Sky Blue (a light aqua color). Natural blue topaz is often confused with aquamarine.
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Topaz is the Sanskrit word for "fire." The more common variety of blue topaz is obtained by the irradiation of colorless topaz. Treated blue topaz is a favorite with jewelers and designers for it is versatility, affordability and availability in a variety of shapes and sizes.
Topaz has the chemical formula: Al2SiO4(F,OH)4 whose strong chemical bonding makes topaz harder than most silicate minerals.
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What is London Blue Topaz?
London blue topaz boasts a unique, inky medium blue color. London blue topaz is the darkest, richest color of topaz available on the market today. It is called "London blue topaz" because London is the home of the largest blue topaz ever found, weighing a whopping 9,381 carats, and displayed in the UK Natural History Museum.
Color is the distinct differentiating factor between the London Blue, Swiss Blue and Sky Blue varieties. London Blue Topaz boats a deeper blue hue, with a tinge of dark tone and saturation, while Swiss Blue Topaz is a vibrant sky blue with a light tone and saturation.
London blue topaz is heat-treated to give it that rich blue color, though you may see a tinge of green on the stone.
Blue topaz is some of the least expensive topaz on the market. The cut often adds as much value to the stone as the color. Of all of the blues, London blue topaz is sought after and the most expensive, retailing at between 10-30 US dollars per carat.
What is the Meaning of Blue Topaz?
Known as the clarity stone, it is believed that blue topaz stimulates open communication and action. It is said that blue topaz is the gemstone of opportunity and a symbol of deep, honest and genuine feelings. This stone has also been associated with great wisdom and is believed to bring the wearer success in their endeavor.
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Blue topaz is also believed to have the uncanny ability to redirect good energies to where they are needed most. Some say that the gemstone helps relieve stress, and migraines, soothe sore throats, and body aches and pains. Being the chakra for the throat, blue topaz is worn around the throat and is alleged to provide relief from throat-related ailments.
Where Does Blue Topaz Come From?
Blue Topaz was first discovered in the Greek Islands, Topazios in the Red Sea by the Romans more than two thousand years ago. Now natural blue topaz is found in the state of Texas in the United States of America, and in the Ural Mountains in Russia. Brazil, Sri Lanka, Nigeria and China also produce blue topaz.
Is Blue Topaz Durable?
Blue topaz registers 8 on the Mohs scale, making it harder than sapphire and tougher than tanzanite. Blue topaz is however brittle and should be handled with care.
London blue topaz has the perfect cleavage and is therefore brittle and easily scratched.
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Where Can I Buy Blue Topaz Jewelry?
Blue Topaz can be bought from a variety of brick-and-mortar stores and also from James Allen, Blue Nile, CustomMade, Angara or White Flash.
Frequently Asked Questions about Blue Topaz
Blue Zircon
Blue zircon is known as one of the modern December birthstones alongside blue topaz and tanzanite. The more traditional December birthstones are lapis lazuli and turquoise.
Known by the mineral name, zirconium silicate, zircon is not to be confused with cubic zirconia, a synthetic diamond simulant. Zircon has the chemical formula ZrSiO4 and boasts a tetragonal crystal structure. Cubic zirconia, by contrast, is made of zirconium oxide and has a cubic crystal structure.
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Zircon has a high refractive index, which can make well-cut zircons especially bright. In fact, zircon is one of the gemstones that looks most like a diamond. Its fire and luster can approximate diamond's and exceed those of sapphire, ruby, and tanzanite.
What Color is Blue Zircon?
Zircons frequently form naturally with brown color, which can turn blue after heat treatment. These heated stones can show stable and vivid blue or sky blue colors. The finest blue zircons will have hues with strong green components and medium tones. You might find some blue zircons referred to by trade names such as starlites or stremlites.
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Heat treatments can also produce green, red, colorless, and honey gold zircons.
What is Blue Zircon's Symbolic Meaning?
Blue zircons are commonly associated with wisdom, confidence, and prosperity. When worn as rings, necklaces, and other jewelry pieces, they are believed to ward off evil spirits, aid sleep, enhance the wearer's intuition, and possess protective auras. Blue zircon is also believed to aid in meditation and getting organized.
Who Can Wear Blue Zircon?
According to Western astrology, anyone whose zodiac sign is Cancer, Gemini, Virgo, Capricorn, or Aquarius can benefit from blue zircon. According to Indian astrology, those whose zodiac sign is Libra or Taurus can also adorn themselves with this gemstone.
Wear blue zircon if you are a writer, painter, or musician. The stone can boost your creative energy.
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Where is Blue Zircon Found?
Blue zircons occur extremely rarely in nature. Virtually all gem-quality blue zircons get their color through heat treatment. Cambodia and Myanmar produce the zircons best suited to turn blue with heat. Malawi has emerged as a possible new source of zircons suitable for heating to blue. In 2021, the Gemological Institute of America published an article on beautiful heat-treated blue zircons reportedly from Maripa, Malawi.
Is Blue Zircon Durable?
Zircons can have a hardness as high as 7.5 on the Mohs scale. This makes them very resistant to scratching and suitable for jewelry use. However, you might want to be extra careful when wearing the stone on a ring. All zircons are very brittle. This means they are very vulnerable to chipping and breaking from accidental impacts. Protective settings that can shield fragile edges and facets are highly recommended.
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Where to Buy Blue Zircon Jewelry
Blue zircon is hard to find in brick-and-mortar jewelry stores but can be bought from some online retailers like James Allen, Blue Nile, and Angara. Prices vary depending on size, hue, and tone.
Fine blue zircon gemstones from one to two carats can average $227 per carat retail. Those from two to five carats can average $337 per carat retail. For additional pricing information on zircons of all sizes and colors, consult our zircon price guide.
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Frequently Asked Questions About Blue Zircon
Tanzanite
Another modern birthstone representing December is tanzanite, a richly colored pleochroic gemstone whose color shows blue and violet, often with purple highlights, depending on what angle you look at it. Tanzanite is a relative newcomer to the gemstone market, the source of which was first uncovered in 1967. Initially believed to be sapphire, the unique and multidimensional appearance of tanzanite suggested it was something else. Gemologists soon identified the gem as an entirely new variety of the gem species zoisite.
Tanzanite was given its name by Tiffany & Co., which recognized the gem's potential immediately after its discovery and became a primary global distributor. To increase consumer recognition of the unfamiliar stone, they named it in honor of its African host country, Tanzania.
Thanks to its popularity, tanzanite was officially added as an additional December birthstone (which is also represented by turquoise and zircon) in 2002. Tanzanite is also given to commemorate a 24th wedding anniversary.
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What Color is Tanzanite?
The answer to this question is more complicated than for most other birthstones. Tanzanite refers to a transparent variety of the mineral zoisite whose body color is some combination of blue and violet hues. It is here that things get interesting because tanzanite is a pleochroic gem. Pleochroism describes a rare ability expressed by only a few gemstone species of showing multiple hues simultaneously depending on which direction you look at the crystal.
Tanzanite shows incredibly strong pleochroism with three distinct colors showing from three different directions. If you hold a crystal one way, it will appear pure or predominantly blue with violet. If you tilt the stone slightly, you will see more of the violet aspects of the stone's color, which is often modified by at least some purple. It is also possible for blue to be combined with purple. Thus, all tanzanite gems show blended combinations of different colors at the same time and the proportion of blue, violet, and purple is entirely unique in each stone. This results in a mesmerizing and multi-dimensional effect that changes constantly as you move and is also affected by the ambient lighting conditions. Every time you look at your tanzanite jewelry, you will see something different and dynamic.
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The best tanzanite stones may mimic sapphires with a pure or predominantly blue color when viewed from the appropriate angle. Thanks to pleochroism, the most exceptional tanzanite stones may also show isolated flashes of red. Gems with a great deal of purple from the violet direction usually cost less, but they are a popular and beautiful choice regardless. Because the colors that you see when you look at tanzanite are variable, the quality and value of the gem is largely dependent on its color saturation, rather than a specific hue. Unfortunately, paler crystals are more common than those with deep color, so the best examples are rare.
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Another contributor to overall color saturation is the size of the crystal. In the majority of cases, smaller stones are less saturated than larger ones. Experts say that gems must weigh at least five carats to be able to achieve the saturation necessary to be considered the finest quality. As larger crystals are less common than smaller ones, it makes sense that the average price-per-carat costs associated with tanzanite rise as carat size increases.
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Gem cutters bear great responsibility when faceting rough tanzanite crystals because how they decide to orient the face-up position of the stone plays a large part in determining which pleochroic color(s) are emphasized from the front view. If cutters want to maximize the size of the gem cut from the rough crystal, they will have to make the face-up position of the gem align with the violet direction. Alternatively, if cutters want the stone to look more bluish, which may be a more valuable color, they need to orient the face-up position of the crystal differently and will ultimately have to shave off more carat weight to achieve this effect. Larger tanzanite crystals are less common than smaller examples, and larger gems fetch higher prices. Thus, cutters usually choose to make bigger gems and most of the jewelry you will find reflects this choice.
Tanzanite is known for often having perfect, eye-clean clarity, meaning that no inclusions can be seen without the help of magnification. Due to the relative abundance of eye-clean stones, those with visible inclusions have a lower value than those without them.
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It is interesting to note that the pleochroism of tanzanite usually displays a brown or yellow-green combination when first mined. The application of heat treatment is required to remove these hues and enhance the remarkable blue and violet colors that the December birthstone is known for. Unlike some other gemstone species whose value can be negatively impacted if treatments are performed, the value of tanzanites that have been heated are not usually impacted significantly. This is due to the fact that heating is so beneficial to the appearance of the gem, and because it is so well-tolerated by the crystal that it often can't be detected. Thankfully, the results of heat treatment for tanzanite are permanent and stable so you don't have to worry about your gems changing color over time.
Tanzanite Meaning
As the source of tanzanite has only recently been identified, it does not share the deep history associated with some of the other birthstones. This means that lore specifically surrounding the stone has not grown and changed over a period of centuries. However, this lack of time-honored legend has not inhibited the popularity of the vibrant gemstone in any way. At times, tanzanite has rivaled the global demand usually reserved for the Big 3: diamond, sapphire, and ruby.
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That is not to say that the December birthstone lacks spiritual associations. As will be discussed below, tanzanite was discovered after it was stumbled upon by a Masai tribesman. There is a question as to why the crystals he found were brightly-colored enough to attract his attention as most tanzanite in the ground are brownish and not nearly as remarkable as the treated gems we regularly see on the market. Some say that this fortuitous change was caused by a lightning strike that sparked a wildfire, raising the temperature on the ground sufficiently for the famous blue and violet hues to emerge. The theory that the gems may have changed their appearance in response to lightning grants them a connection to the wild power and magic of the natural world.
Additionally, the rich colors that tanzanite exhibits do have meanings in themselves. Here are just a few brief examples:
- Blue is considered deeply spiritual because it is the color of both the heavens and life-giving water. Blue stones in general are thought to provide vitality both physically and emotionally.
- Purple is a noble color often adopted by royalty and thought to provide strength.
- Purple and violet are both associated with the Crown Chakra located at the top of the head. They are powerful colors connected to wisdom and intuition.
With the potential to display all three of these colors simultaneously, tanzanite is a special gem for the wearer indeed.
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Where Does Tanzanite Come From?
Masai tribesman Ali Juuyawatu discovered tanzanite while he was traveling in the East African country of Tanzania in 1967. He came across a cluster of beautiful gems poking out of the ground in the Merelani Hills region of the Lelatema Mountains. Ali contacted a local prospector named Manuel d'Souza who initially staked mining claims thinking that the vibrant and highly transparent violet and blue crystals might be sapphire. It quickly became clear that they were something entirely new. People flocked to the location and commenced mining operations before even confirming what species of gemstone they were gathering. It turned out that the discovery was extremely lucky because that small area near Mount Kilimanjaro remains the only known source of tanzanite.
While the Merelani Hills have produced enough tanzanite to popularize the gem on a global scale, supply remains limited, and the gem is considered rare. Indeed, it is far rarer than any of the Big 3. Unfortunately, we know that all deposits must become exhausted at some point. With this in mind, experts say to treasure your tanzanite jewelry because the availability of the gem will eventually decrease. Some estimate that it could run out entirely within a generation if another deposit is not located.
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Is Tanzanite Durable?
Tanzanite has a hardness ranking of 6 to 7 on the Mohs hardness scale, making it softer than some other birthstones like diamond and sapphire but stronger than some varieties of opal. The surface of tanzanite can be scratched if permitted to rub against other objects and it can chip if impacted. Protective settings help to protect the sides of your gems during wear, but it is best to remove your rings and bracelets if you know that you are going to be particularly active.
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Be sure to be gentle with your tanzanite jewelry during cleaning. It is best to use mild, soapy water with a soft cloth to avoid scratching the surface of the gem. Because tanzanite is sensitive to high temperatures, avoid ultrasonic machines and steam cleaners.
Tanzanite Rings and Jewelry
While it may not be wise to wear your relatively delicate tanzanite rings and bracelets on a daily basis, designs featuring the stone can be breathtaking! The richness of the color coupled with excellent clarity makes for a showstopping effect that is perfect for special occasions. As earrings and pendants are at little risk of damage, you can wear those without fear. Fortunately, tanzanite is available at a range of price points so there are jewelry options available that can be accommodated by most budgets.
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There is no global standard of grading for tanzanite like there is for diamonds, so laboratory reports which may accompany gems will not list a formal "grade". They will, however, comment on the quality of the color, clarity, and cut of faceted gems. If a seller advertises a stone according to a specialized rating system like A-AAAA, ask for specifics so that you are fully informed about the qualities of the stone which you are buying. If your seller is honest and reputable, and you like what you see, trust your instinct.
The most common tanzanite shapes you will see are oval and cushion cuts. A few of the finest gems may be fashioned into bold emerald cuts whose large table facet allows for an uninterrupted view of the interior of the stone. Remember that the quality of the cut is especially important in maximizing the multidimensional color of tanzanite, so it is best to stick with stones that were faceted with care.
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It is important to keep in mind that industry professionals consider heating to be an acceptable treatment for tanzanite. It is estimated that approximately 95% of the gems you will see on the market have been heat-treated to achieve their blue and violet pleochroic color. Some lower-quality tanzanite gems are coated with compounds containing elements like cobalt or titanium to improve their color and luster. Gems that have coatings are not a great option for jewelry because the coverings hide the true appearance of the stone and can become scratched, discolored, or peeled off over time. Reputable dealers will always disclose if any of their inventory is coated, which is one of the reasons why you should seek out a professional when shopping for fine jewelry.
Frequently Asked Questions about Tanzanite
Turquoise
Turquoise is the traditional December birthstone. Presenting as an opaque blue-green mineral, it is made up of hydrated copper phosphate and aluminum. Turquoise has a distinct tri-clinic structure. It can be waxy to the touch, glassy, or dull in appearance.
Turquoise has been prized and adorned as an ornamental stone for thousands of years. Generally, due to its poor wearability, the highest grades of turquoise are reserved for inlay and carving. However, you can buy some beautiful cabochon stones for jewelry like rings, necklaces, earrings, and bracelets. We recommend you purchase turquoise in a strong setting like a bezel to protect the stone.
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What is the December Birthstone Color?
Turquoise is best known for its blue hues, but these can vary from bright blue-green to green to yellowish-green. The stone may also present brown or black spots or streaks running through it.
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What is the Meaning of Turquoise?
The word "turquoise" is a French word "pierre tourques" or "Turkish stone," probably due to the stone's Turkish origins. The stone was first found in Egypt, as early as 4000 BC, making it one of the oldest gemstones in history. It arrived in Europe from Turkish sources around the thirteenth century.
Turquoise is believed to symbolize prosperity, love and good fortune. If you believe in gemstone healing properties, then you can wear turquoise to boost positive energy and promote happiness, honesty and spirituality.
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Where Does Turquoise Come From?
Rich deposits of turquoise are found in parts of North America, specifically Nevada and Arizona. Egypt, Iran, Bulgaria, and China also produce turquoise.
Is Turquoise D urable?
Turquoise stone has a hardness of 5-6 on the Mohs scale, which makes it too soft for certain types of jewelry. However, there are treatments that can stabilize the stone and make it suitable to wear.
Where Can You Buy Turquoise Jewelry?
Turquoise jewelry is available for sale in a variety of retail stores and can be conveniently bought online from Blue Nile and Angara. If you have a specific design in mind, check out CustomMade for a bespoke turquoise piece.
Frequently Asked Questions About Turquoise
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Elizabeth Gathu
Emily Frontiere
Emily Frontiere is a GIA Graduate Gemologist. She is particularly experienced working with estate/antique jewelry.
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