A Matter of Brilliance is a professional jewelry appraisal company based in Newton, MA, founded by Aimee Berrent, Graduate Gemologist. Our appraisals can be used to:
Banish those winter blues with three beautiful, blue December birthstones: tanzanite, zircon, and turquoise. As the American Gem Society writes, “These gems range from the oldest on earth (zircon), to one of the first mined and used in jewelry (turquoise), to one of the most recently discovered (tanzanite).”
To start with the newest, this gem was discovered, not surprisingly, in Tanzania in 1967. Naturally, the stone can have undertones of brown. Since heating a stone will bring out its brilliant blue/purple tones, most tanzanite jewelry is heat-treated. The clear blue of tanzanite can look like a sapphire. But it’s not as hard as the sapphire, so it’s better in earrings and pendants than in rings.
- Tanzanite can show different colors from different angles; a blue stone is usually more expensive than a purple one.
- The mines have been nationalized, so tanzanite supplies can be limited; however, it continues to grow in popularity.
Don’t confuse this with cubic zirconia—this is a natural gemstone, the oldest mineral on earth. While natural zircons can look brownish, heat treatments turn them into brilliant blue stones. Zircons rate a strong 7.5 on the Mohs hardness scale, but faceted edges can chip.
- The oldest zircons from Australia date back 4.4 million years.
- Healing properties are believed to include warding off evil, promoting sleep, and bringing prosperity to the wearer.
This stone likely evokes images of the Southwest—big rings, necklaces, and belt buckles. The U.S. is the largest producer of this beautiful, bold blue stone. Turquoise rates only a 6 on the Mohs hardness scale, which means it’s one of the softer stones. That’s why it is so popular for carving.
The stone is actually a conglomeration of microscopic crystals. The closer the crystals are packed together, the finer the stone’s texture. The black lines you find in turquoise are called “matrix” and are from the surrounding stone the turquoise was formed in…matrix actually increases the value of a stone. Turquoise gets its color when rainwater dissolves soil’s copper (which brings the blue to the mineral). Iron and chrome result in green tones.
- Be careful to keep your turquoise jewelry out of extreme sunlight. Makeup, perfume, and oils can also damage it.
- Fine-textured turquoise has an attractive, waxy luster when it’s polished.
- The most prized color of turquoise is robin’s-egg blue or sky blue, most commonly found in Iran (it’s called “Persian blue”).
- According to the American Gem Society, a turquoise’s value is determined by its color, matrix, hardness, and size.
Banish the winter blues with one or more of these beautiful December birthstones. And when it comes to old or new jewelry, don’t forget to call me so they can be appraised. I want you to enjoy your jewels and keep them safe, for years to come.
Brilliantly yours, Aimee