Facts About December’s Birthstones

Turquoise gem stone

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The official December birthstones are turquoise, blue topaz, and tanzanite. All three gemstones are cooler toned and beautiful in their own right, and picking between them can be a challenge.

The birthstones of December might be similar in color, but they are more different than they are alike. Factors such as price, availability, and common cuts help distinguish these gemstones from one another.

If you are trying to decide which December birthstone is right for you, read through these gemstone facts to learn more about each one. If you still can't choose, who says you can't wear all three together?

Turquoise Facts

turquoise facts
  • Most turquoise on the market is partially to fully opaque. Transparent turquoise gemstones are uncommon.
  • Turquoise usually forms in the crevices of other rocks. These darker rocks can create a matrix effect that looks like veining or marbling throughout the stone.
  • Turquoise is an ancient stone that dates back 3,000 years or more.
  • Persian turquoise is known for its intense color and lack of any matrix of veining.
  • Turquoise has been mined in Iran, China, and in the US states of New Mexico, Nevada, and Arizona.
  • Most modern turquoise has been enhanced to increase its durability and create more vivid colors.
  • Because turquoise is porous and often treated with resins, you should never clean turquoise jewelry in an ultrasonic machine. Use a gentle method and never submerge the gemstone in liquids.
  • Some fine turquoise specimens command top dollar, including some antique pieces that are authenticated and proven to be natural. However, most turquoise jewelry is cast in sterling silver and can be purchased for under a few hundred dollars.
  • Turquoise ranks between five and six on the Mohs Scale of Hardness, so it is very susceptible to scratching and chipping.
  • Turquoise is not usually faceted like other gemstones. It is shaped into cabochons, beads, or is carved into fancy shapes like flowers.
  • Be careful when purchasing vintage jewelry with turquoise stones. There were simulated turquoise stones made out of glass as far back as the 1800s. If you are unsure, have the gemstone tested by a professional.

Blue Topaz Facts

Raw blue topaz
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  • Blue topaz is a birthstone for December that is sometimes interchanged with zircon.
  • Most blue topaz is colorless topaz that has been treated to turn blue.
  • Blue topaz ranks eight on the Mohs Scale of Hardness, which means it is more durable than tanzanite.
  • London blue, swiss blue, and sky blue topaz are the three more commonly marketed varieties of blue topaz. Each is a slightly different shade of blue that is produced using manmade treatments.
  • Because most blue topaz is treated, you should not clean this gemstone with ultrasonic machines or steamers.
  • Topaz is mined and manufactured in parts of the US, China, Mexico, and Russia.
  • This gemstone is easily produced and therefore readily available in large sizes and fancy cuts. You'll be able to purchase a blue topaz gemstone for significantly less money per carat than a comparable tanzanite gemstone. However, blue topaz is usually more expensive than similarly treated turquoise.

Tanzanite Facts

three tanzanite gems
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  • Tanzanite wasn't discovered until the 1960s, so it is a relatively newer gemstone.
  • Tanzania is the only place in the world that tanzanite has been mined and manufactured on a commercial basis.
  • Tanzanite ranks between six and seven on the Mohs Scale of Hardness. It is susceptible to scratching and chipping by any gemstone that is harder than it, like sapphire or diamond.
  • Most tanzanite on the market has been treated to enhance the violet or purple color. If you are looking for natural tanzanite, find one that has a gemological report.
  • Since tanzanite is more fragile, it's recommended to set the stone in earrings or a necklace. Rings can take a beating, so if you have a tanzanite ring, don't wear it every day. Tanzanite would not make an ideal engagement ring.
  • If you decide to set tanzanite in a ring, be sure that the setting has large protective prongs. You could also bezel set the stone to protect all the edges.
  • Tiffany & Co is one of the most prolific tanzanite designers and has marketed the gemstone on and off since its discovery. They have been credited with the instant success of the stone.
  • One of the more desirable features of tanzanite is known as pleochroism, which means that the gemstone will show different colors depending on the angle it's viewed.
  • Some tanzanite can be so blue that it is virtually indistinguishable from sapphire to the untrained eye.