Zircon- The December Birthstone

All you December babies are blessed with 3 distinct birthstones. One of them is Zircon, an underrated gemstone. It is usually confused with cubic zirconia. The reason is similarity in sounds along with use. Both of these are used as diamond simulants. Here’s a less known fact about the December birthstone- zircon is a spectacular natural gemstone available in a variety of colors.

Origin of the name “Zircon”:

Zircon derives its name from the Persian word “zargun”. Zargun means gold-colored. Some other people trace the origin of the name to the Arabic word “zargun” which means vermillion. Well, you’ll find zircon in multiple colors – spanning red, orange, yellow, green, blue, and brown. So, both the origins can be trusted. 


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 diamonds. 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.

Origin of the stone and where it is found:

4.4 billion years ago, Zircon was found in Australia. 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.

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 sand 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. As if they were recording these changes like a time capsule. Zircon contains the radioactive element uranium, which changes the gemstone’s chemical structure and color over time. Well, that gives us important clues about the formation of our planet.

Learn more about the fascinating world of gems and gemology at JK

Physical Properties:

Chemical Classification Silicate
Color Usually yellow, brown, or red. Also colorless, gray, blue, and green.
Streak Colorless. Usually harder than the streak plate.
Luster Vitreous to adamantine, sometimes oily.
Diaphaneity Translucent to transparent
Cleavage Imperfect
Mohs Hardness 7.5
Specific Gravity 4.6 to 4.7
Diagnostic Properties Hardness, luster, specific gravity
Chemical Composition ZrSiO4
Crystal System Tetragonal
Uses Ore of zirconium metal, ore of zirconium dioxide, whitening agents, white pigment, gemstones, radiometric dating.

Optical Properties:



Crystal System

Tetragonal  (4/m2/m2/m)

Crystal Habit

Microscopic crystals


Poor {110} prismatic,  Poor {111} pyramidal





Specific Gravity



Thermoluminescent, cathodoluminescence, may fluoresce under UV light

Optic Sign

Uniaxial (+)

Optic Orientation

length slow

Max Birefringence

0.036 – 0.0650.036 – 0.053 (natural non-metamict)

Beliefs associated with Zircon:

During the Middle Ages, people believed that zircon gemstones could induce sound sleep, ward off evil, and bring prosperity and wisdom.

Blue zircon was popular during Victorian times and frequently adorned English estate jewelry from the 1880s. Zircon with a cloudy or smoky appearance was popular in mourning jewelry.

During the 1920s, heat treatment became a customary practice to enhance the color of zircon gemstones for jewelry. Zircon has also been used in the decorative ceramics industry.

Zircon is a popular gemstone among collectors for its range of colors. But consumers seem most enamored with the blue variety and otherwise confused about the history and possibility of this expansive gemstone.

Zircon’s value and a mini buying guide:

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 costs makes zircon a popular gemstone with collectors.

Zircon gems generally follow the same value factors as diamonds. 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. It comprises 80 percent of all zircon sales and commands 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 a zircon depends on its color. Blue and green gemstones come in sizes up to 10 carats, while orange and yellow go 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 gem or any other color, you will find a zircon just right for your style.

Learn more about the fascinating world of gems and gemology at JK

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