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.