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. Zircon commonly occurs 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 from Australia dates back 4.4 billion years. Australia still leads the world in zircon mining, producing 37 percent of the world’s supply. Other sources include Thailand, Sri Lanka, Tanzania, Cambodia, Canada, and the United States. Since the Middle Ages, people have believed that zircon can induce sleep, ward off evil, and promote prosperity.
Zircon is the oldest mineral on Earth, dating back more than 4.4 billion years. Found in the Earth’s crust, it’s common in most sands and sedimentary deposits, as well as metamorphic rocks and crystallized magma. Due to its chemical makeup, zircon has survived ages of geologic events like erosion and pressure shifts—recording these changes like a time capsule. Zircon contains the radioactive element uranium, which changes the gemstone’s chemical structure and color over time, giving us important clues about the formation of our planet. During the Middle Ages, people believed that zircon could induce sound sleep, ward off evil, and bring prosperity and wisdom. Blue zircon, in particular, was popular during Victorian times, and frequently adorned English estate jewelry from the 1880s. Zircon with a cloudy or smoky appearance was also popular in mourning jewelry. In the 1920s, heat treatment became customary practice to enhance the color of zircon gemstones for jewelry. Zircon has also been used in the decorative ceramics industry. While zircon is a popular gemstone among collectors for its range of colors, consumers seem most enamored with the blue variety, and otherwise confused about the history and possibility of this expansive gemstone. Zircon is often confused with Cubic Zirconia (CZ). CZ is one of the best-known, man-made simulants and is the crystalline form of zirconium dioxide (ZrO2). Zircon is a naturally-occurring mineral, which is zirconium silicate (ZrSiO4).
Whether you’re buying blue zircon to celebrate a December birthday, or selecting another shade just to own a gorgeous piece of Earth’s oldest history, zircon offers many options. A wide range of colors at relatively low cost make zircon a popular gemstone with collectors. While zircon generally follows the same value factors as diamonds, it’s best to visit an American Gem Society jeweler who can help you select the right gemstone for you. Zircon is available in a rainbow of colors. Reddish brown earth tones are common, but bright red or green gemstones have higher market value. Blue zircon is the most popular variety, comprising 80 percent of all zircon sales and commanding the highest prices. Blue is almost always the result of heat treatment. Zircon is often cut in the brilliant style to showcase its diamond-like luster and fire. Facets must be cut carefully (to avoid chipping this brittle stone) and properly (to avoid the blur caused by zircon’s strong double refraction). The size of zircon depends on its color. Blue and green gemstones come in sizes up to 10 carats, orange and yellow up to five. Rare red and purple stones are typically smaller. Because zircon is one of the heaviest gemstones, it appears smaller than other gemstones of equal carat weight. Often considered the best-looking natural substitute for diamond, zircon is gaining popularity—not just in colorless form, but across the spectrum. Whether you’re seeking a birthday blue or any other hue, you can find the zircon just right for you.