DECEMBER BIRTHSTONES TURQUOISE, TANZANITE, AND ZIRCON
Admired since ancient times, turquoise is known for its distinct color, which ranges from powdery blue to greenish robin’s egg blue. It’s one of few minerals to lend its name to anything that resembles its striking color.
The word “turquoise” dates back to the 13th century, drawing from the French expression pierre tourques, which referenced the “Turkish stone”, brought to Europe from Turkey.
Ancient Persia (now Iran) was the traditional source for sky blue turquoise gemstones. This color is often called “Persian blue” today, regardless of its origin. The Sinai Peninsula in Egypt was also an important historical source of turquoise gems.
The U.S. was once the world’s largest turquoise supplier. Nevada, New Mexico, California, and Colorado have produced turquoise, but Arizona leads in production by value, as well as quality. The Kingman mine in Arizona is a historically important source that is known for producing intense blue turquoise. Now closed to turquoise mining, Arizona’s Sleeping Beauty mine was a prolific producer for more than four decades. The stone’s popularity here makes it a staple in Native American jewelry.
Today, China is the world’s largest producer of this December birthstone. Hubei Province, in central China, is the source of most of the gem-quality turquoise currently being mined there.
Turquoise is found in arid regions where rainwater dissolves copper in the soil, forming colorful nodular deposits when it combines with aluminum and phosphorus. Copper contributes blue hues, while iron and chrome add a hint of green.
Some turquoise contains pieces of host rock, called matrix, which appear as dark webs or patches in the material. This can lower the stone’s value, although the uniform “spider web” pattern of Southwestern turquoise is attractive.
Turquoise is sensitive to direct sunlight and solvents like makeup, perfume, and natural oils. The hardest turquoise only measures 6 on the Mohs scale, which made this soft gemstone popular in carved talismans throughout history.
From ancient Egyptians to Persians, Aztecs and Native Americans, kings and warriors alike admired turquoise for thousands of years. It adorned everything from jewelry to ceremonial masks to weapons and bridles—granting power and protection, particularly against falls.
The turquoise birthstone was thought to possess many beneficial powers, like guaranteeing health and good fortune. From the 13th century on, it was believed to protect the wearer from falling (especially off horses), and would break into several pieces at the approach of disaster. Hindu mystics maintained that seeing a turquoise after beholding the new moon ensured fantastic wealth. The turquoise birthstone also played an important role in the lives of Native Americans. The Apache thought turquoise could be found by following a rainbow to its end. They also believed that attaching the December birthstone to a bow or firearm made one’s aim more accurate. The Pueblo maintained that turquoise got its color from the sky, while the Hopi thought the gem was produced by lizards scurrying over the earth. This December birthstone adorns the funerary mask of King Tut, who ruled Egypt more than 3,000 years ago. It also appears in jewelry belonging to more modern royalty: Wallace Simpson (1896–1986), Duchess of Windsor (the woman for whom King Edward VIII gave up his throne), wore a famous amethyst and turquoise necklace made by Cartier. Turquoise is also the gem of the 11th wedding anniversary. In European tradition, the gift of a turquoise ring means “forget me not.” Turquoise is considered a national treasure in Tibet, where it is believed to grant health, good fortune and protection from evil. December's birthstone also imparts peace to those who wear it.
Some turquoise is treated to improve its durability, appearance and polish. Turquoise can be dyed or chemically enhanced by adding an epoxy or acrylic resin for greater hardness or better color. Also seen are cavities filled with a metal-loaded epoxy to imitate pyrite inclusions.
Turquoise is generally stable to light, but high heat can cause discoloration and breakage. Your turquoise birthstone can be damaged by acids, and it can be discolored by certain chemicals, cosmetics and even skin oils or perspiration. It’s safe to clean turquoise jewelry with warm, soapy water, but this December birthstone should never be cleaned with steam or ultrasonic cleaners. Heat or solvents can damage the treated surfaces on some turquoise.
Tanzanite is the exquisite blue-purple variety of the mineral zoisite that is only found in one part of the world. Named for its limited geographic origin in Tanzania, tanzanite has quickly risen to popularity since its relatively recent discovery.
Tanzanite is a relative newcomer to the world of colored stones, and it was one of the most exciting gem discoveries of the 20th century. Blue stones emerging from Tanzania were identified as the mineral zoisite in 1962. Zoisite had been around more than a century and a half before this rare blue variety was found in 1967. Trace amounts of vanadium, mixed with extreme heat, cause the blue-purple color—which ranges from pale blue to intense ultramarine with violet undertones.
Due to pleochroism, tanzanite can display different colors when viewed from different angles. Stones must be cut properly to highlight the more attractive blue and violet hues, and deemphasize the undesirable brown tones.
The majority of tanzanite on the market today is heat treated to minimize the brown colors found naturally, and to enhance the blue shades that can rival sapphire. The resulting color is permanent, and there are no additional durability concerns.
Tanzanite is still only found on a few square miles of land in Tanzania, near majestic Mount Kilimanjaro. Its price and availability are directly tied to mines in this region, most of which are now slowing production significantly.
Between its deep blue color and its limited supply, tanzanite is treasured by many, even if your birthday is not in December.
Tiffany & Co. believed that tanzanite had international appeal and became its main distributor. In 1968, Tiffany launched a major advertising campaign to promote it. With its vivid colors, high clarity and potential for large cut stones, tanzanite quickly became a sensation. Today, it is not only a December birthstone, but it is also the gem for the 24th wedding anniversary.
This December birthstone (6 to 7 on the Mohs scale of hardness) is resistant to the effects of normal heat, light and common chemicals. Still, the December birthstone may crack if exposed to very high temperatures or sudden temperature changes, and it abrades easily. It can be attacked by hydrochloric and hydrofluoric acids. Your tanzanite birthstone is best set in earrings or pendants. While not recommended for daily wear in a ring, with a protective mounting and some care this December birthstone can be an attractive special-occasion jewel. Warm, soapy water is the best way to clean this December birthstone. Ultrasonic and steam cleaners are never recommended for tanzanite. ZIRCON
Zircon is an underrated gemstone that’s often confused with synthetic cubic zirconia due to similar names and shared use as diamond simulants. Few people realize that zircon is a spectacular natural gemstone available in a variety of colors.
The name “zircon” likely comes from the Persian word zargun, meaning “gold-colored.” Others trace it to the Arabic zarkun, meaning “vermillion.” Given its wide range of colors—spanning red, orange, yellow, green, blue, and brown—both origins are plausible. Colorless zircon is known for its brilliance and flashes of multicolored fiery light, which have resulted in centuries of confusion with diamond.
Zircon commonly occurs as brownish red, which can be popular for its earth tones. However, most gem-quality stones are heat treated until colorless, gold or blue (the most popular color). Blue zircon, in particular, is the alternative birthstone for December.
Color differences in zircon are caused by impurities, some of which (like uranium) can be slightly radioactive. These gemstones are also treated with heat to stabilize the radioactivity.
While radiation can break down zircon’s crystal structure, it plays a crucial role in radiometric dating. Zircon, the oldest mineral on Earth, contains important clues about the formation of our planet.
Colorless zircon, known as Matura Diamond, displays brilliance and flashes of multicolored “fire” that can rival fine diamond. There’s one key difference though: Zircon is more brittle. Though it measures 7.5 on the Mohs scale of hardness, its faceted edges can chip.
Zircon found in Australia dates back 4.4 billion years. Australia still leads the world in zircon mining, producing 37 percent of the world’s supply. Australia’s Harts Range is known for producing zircon birthstones in yellow-brown, orangey brown, pink and purple. Go there and you’ll see open savannahs, dry stream beds and low-lying hills that meet the horizon. Zircon Hill is where this December birthstone is mined.
Other sources include Thailand, Sri Lanka, Tanzania, Cambodia, Canada, and the United States.
Sri Lanka's wealth of gems is legendary: Sapphire in various colors, ruby, alexandrite, spinel, tourmaline, moonstone, and quartz are some of the gem minerals unearthed there. So is the December birthstone zircon.
Since the Middle Ages, people have believed that zircon gemstones can induce sleep, ward off evil, and promote prosperity. In the Hindu religion, zircon alternates with hessonite garnet as one of the nine gems of the navaratna. When worn together, the nine gems protect the wearer and bring wealth, wisdom and good health. Victorians had a fondness for blue zircon. Fine specimens can be found in English estate jewelry from the 1880s.
Zircon ranges from 6 to 7.5 on the Mohs scale of hardness. It is commonly heat treated to produce blue and colorless varieties, as well as orange, yellow and red. The gem is generally stable when exposed to light, but some heat-treated stones may revert to their original colors (usually light brown) after prolonged exposure to bright light. Exposure to heat can alter the color of some zircon. This December birthstone is stable when exposed to chemicals. Because zircon tends to abrade, it is best to avoid wearing it in rough conditions, such as while gardening, playing sports or doing dishes. Clean your zircon using a soft brush and mild soap in warm water. Ultrasonic and steam cleaners are not recommended for this December birthstone.