For those lucky enough to be born in this festive month, December has three birthstone options to choose from: tanzanite, zircon, and turquoise. They are all known for their beautiful blue shades, and they are all relatively affordable, but each has distinctive features that make it unique. Here’s what you need to know to decide which is the best fit for you.
Tanzanite: Discovered in 1967, this rare variety of the mineral zoisite is found in only one spot in the world, near Mount Kilimanjaro in Tanzania. It is prized not only for its rich blue hue, which rivals that of sapphire, but for its pleochroism, which means the stone can display different colors when viewed at different angles. This gem has a Mohs hardness of 6.5 to 7, which makes it most suitable for use in earrings or necklaces, or in rings worn for special occasions. When you’re purchasing, look for stones with a deeply saturated hue, as color is the most important factor in determining tanzanite’s value. Due to the extremely limited source for this gemstone, experts expect its price to rise in the years to come.
Zircon: Zircon is the oldest mineral on earth, at more than 4.4 million years old. While the blue variety of this stone is the most popular with collectors, accounting for about 80 percent of the zircon sold, it comes in a variety of shades that are used as gems. This gemstone has high luster and double refraction, which gives it a pronounced fire—it is often cut in the brilliant style to enhance this effect. In the Middle Ages, it was believed that zircon could ward away evil spirits and bring prosperity to its owner. Blue zircon was also particularly popular in Victorian times. Zircon is a 7.5 on the Mohs scale, but it is somewhat brittle, so it can be prone to chipping. As with other types of transparent gems, the most valuable zircons have deep color and no eye-visible inclusions.
Turquoise: Turquoise has been prized throughout history in both the Old World and the New, from Egypt and Persia to the pre-Columbian Americas. This opaque mineral, which ranges from sky-blue to green in color, is a compound of hydrated copper and aluminum phosphate. Its relative softness on the Mohs scale (5 to 6) has made it an attractive material for carving as well as for jewelry. Turquoise usually forms within a host rock, limonite or sandstone, which may create markings called matrix within the stone. Turquoise can also vary in porosity and texture depending on the exact conditions of its formation. Turquoise that is dense, finely textured, and has no inclusions of host rock will command a higher price than a coarser stone or one with significant matrix. A bright, even, robin’s egg blue is considered the most valuable color for this stone. Turquoise is vulnerable to chemicals and high heat, so it should be worn with extra care.
No matter which December birthstone you decide on, Auction King regularly stocks a variety of rings, pendants, bracelets, and more. Their live online auction format gives you the opportunity to purchase high-quality jewelry at below-market prices from the comfort and convenience of your own home. Sign up for a free account today and start browsing.