Zircon (Zirconium Silicate ZrSiO4). Mohs hardness:  6.5 – 7.5 Refractive Index:  1.777 – 1.987

Lustrous, fiery, and considered to be among the oldest minerals on earth, the Zircon is one of the most fascinating gemstones in existence. Known for its durability, as well as its resistance to chemical attack, scientists have called the Zircon, a “tiny time capsule”, describing it as “the most reliable natural chronometer that we have when we want to look at the earliest part of Earth history.”

The intriguing history of a Zircon begins with its formation: formed by crystallization from a magma or in metamorphic rocks, the Zircon possesses a remarkable ability to not only survive geologic events – some of which may last millions of years – but to record those events in its crystal rings, similar to the rings found in tree trunks. Imagine wearing one of these!

These ever-intriguing gemstones sometimes offer another unusual feature: radioactivity. In a rare example of an animated life cycle in a stone, these radioactive elements can cause metamiction, an ongoing process in which the stone’s inner crystal structure is slowly destroyed.

While this very slight radioactivity is at levels that pose no health risk when used in jewelry, the trace elements trigger the vibrant color diversity found among Zircons. Ranging from yellows and browns, oranges and reds, greens and blues, it is believed that the Zircon’s name comes from the Persian word for the stone, zargun, which means “gold-colored”.

The Zircon also appears in ancient Hindu poetry, as the leaves of the Kalpa Tree, a glowing tree covered in gemstone fruit.  The Zircon has been considered as a talisman for travelers, a deliverer of financial success, and a protector against occurrences such as jealousy, envy or lightning strikes, as well as harmful energy emitted by celestial bodies in our solar system. Each color offers a different benefit: for instance, a pink Zircon allegedly aids the wearer in astral travel; light yellow boosts sexual power; and red promotes healing. The colorless Zircon, which is unfortunately often confused with the artificial cubic zirconia, is thought to stimulate mental awareness and clear thinking.

The Zircon’s high refractive index and strong dispersion – its fire – gives the stone its great brilliance. Legend has it that the Zircon’s owner must maintain the gemstone’s shine – otherwise its power transforms from positive to negative.

An important identification mark for all Zircons, with the exception of the green variety, is the strong double refraction easily seen under the loupe at the facet edges. The illusion of “double refraction” is actually the doubling of the facet junctions, thereby creating a line where two facets meeting in the back appear either doubled or blurred when viewed from the top. Being responsive to a basic heat treatment, the Zircon will glow in bright yellow or soothe in pensive blue, both considered to be the most desirable colors of the Zircon. 

Zircon is mined in Cambodia, Sri Lanka, Thailand, Myanmar, Australia, and other countries.