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Zircon

Zircon is a colorful gem with high refraction and fire that’s unfairly confused with cubic zirconia.

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Cushion Cut

This 21.05-ct. cushion cut, orange zircon is from Tanzania.

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Fall Color

This gem displays a warm autumnal reddish brown.

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Seeing Double

Zircon’s strong double refraction causes double images of facets.

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Cinnamon Brown

Like this rare untreated 48.50-ct. crystal, zircon is often brownish.

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Pointed Cap

Zircon crystals are often four sided and capped with pyramid shapes.

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Ubiquitous Gem

Zircon crystals grow in many different types of rock.

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Tools

Overview

About Zircon

Colorless zircon is known for its brilliance and flashes of multicolored light, called fire. These zircon properties are close enough to the properties of diamond to account for centuries of confusion between the two gems.

Zircon occurs in an array of colors. Its varied palette of yellow, green, red, reddish brown, and blue hues makes it a favorite among collectors as well as informed consumers.

Zircon Description Zircon History and Lore

Birthstones & Anniversaries

Zircon is a birthstone for the month of December, along with turquoise and tanzanite.

4.4 billion

Zircon found in Australia is the oldest mineral on earth: 4.4 billion years old.


Metamictization

Zircon sometimes contains traces of uranium, irradiating itself and changing its properties.


Matara

Colorless zircon is called “Matara” zircon after a city in Sri Lanka near where it is mined.


Facts

  • Mineral: Zircon
  • Chemistry: ZrSiO4
  • Color: Blue, red, yellow, orange, brown, green
  • Refractive index:
  • High: 1.925 to 1.984 (+/- 0.040)
  • Medium: 1.875 to 1.905 (+/- 0.030)
  • Low: 1.810 to 1.815 (+/-0.030)
  • Birefringence: 0.000 to 0.059 (low to high)
  • Specific gravity: 3.90 to 4.73
  • Mohs Hardness: 6 to 7.5 (low to high)

Where It's Found

map

Treatments

There are a number of processes used to alter the color, apparent clarity, or improve the durability of gems.

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Synthetics

Some gemstones have synthetic counterparts that have essentially the same chemical, physical, and optical properties, but are grown by man in a laboratory.

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Imitations

Any gem can be imitated—sometimes by manmade materials or by natural materials chosen by man to impersonate a particular gem.

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gem love

Why We Love This Gemstone

1
Geological Clock

With radioactive trace elements that tick off time, zircon is a geological clock that tells us about the early earth.

2
Brilliance and Fire

Zircon has very high luster, refractive indices, and dispersion, giving it lots of brilliance and rainbow flashes of fire.

3
Double-double

Zircon’s pronounced double refraction means you can see twice as many facets and twice as much fire.

Quality Factors

Among consumers, blue is the most popular color of zircon.

Color

quality factors

The most valuable colors of zircon are blue, bright red, and green.

Clarity

quality factors

Zircon is often eye-clean. Gems with noticeable inclusions are less valuable.

Cut

quality factors

To maximize its brilliance, zircon is most often cut in rounds and ovals.

Carat Weight

quality factors

Zircon in fine quality is rare in large sizes. Zircon weighs more than most gems of like size.

Zircon Quality Factors: The Comprehensive Guide

Research

Explore sources, gemological research, and the role of gems in history.

Zircon from the Harts Range, Northern Territory, Australia

Maxwell J. Faulkner and James E. Shigley , Dec 1, 1989 Read Article

Brownish Red Zircon from Muling, China

Tao Chen, Hao Ai, Mingxing Yang, Shu Zheng, and Yungui Liu , May 9, 2011 Read Article

The Elahera Gem Field in Central Sri Lanka

Mahinda Gunawardene and Mahinda S. Rupasinghe , Jun 1, 1986 Read Article

Gem Wealth of Tanzania

Dona M. Dirlam, Elise B. Misiorowski, Rosemary Tozer, Karen B. Stark and Allen M. Bassett , Jun 1, 1992 Read Article