Zircon: sparkling in the shadows

Zircons are derived from igneous and metamorphic rocks where they are formed as prismatic crystals and grains.

Today, the gem is available in a spectrum of colours from clear to yellow, red, orange, brown, yellow-green, bright leaf-green, dark green and sky-blue.

Sky-blue is the most sought-after zircon. These zircons are called 'star light'. To yield the most desired optical effect, zircons are usually fashioned into brilliant cuts.

It is apparent that zircons derived their name from their colour: the word 'zircon' comes form the Arabic word zargoon, meaning 'vermilion'. In Persian, zargoon means 'gold-coloured'. Perhaps on account of its similar name, many people confuse zircon with cubic zirconia. Zircon is a genuine mineral, while cubic zircons are laboratory-grown diamond imitations.

Another reason for the confusion may be that the zircon is often used as a diamond alternative. The two stones resemble one another in lustre: they each have a high refractive index. For this reason, it is believed that even some experienced jewellers have mistaken one for the other.

It is simple to distinguish between the two by examining a worn zircon for chips. A diamond would not suffer the same damage as it is much less brittle than its softer cousin. While zircons are relatively hard, rating 7-7.5 on Moh's scale, hardness may not be consistent through the entire stone. The cleavage point on a zircon is imperfect and irregular, so the stone can be chipped if rubbed against other objects.

Zircons have been used for many purposes throughout history, with a variety of spiritual powers assigned to them. In the middle ages, zircon was said to make its lucky wearers appear more beautiful and also to bring them glory, riches, honour and wisdom.

Zircon was also said to endear wearers to God and merchants would carry the stone as a talisman to protect them from bandits.

In these times, the gem was used as a barometer, reportedly clouding up and become dull when bad weather was imminent and shining in anticipation of sunny days. The stone had many medicinal uses: it was used as a remedy for fevers; a zircon tablet worn over the heart was believed to help strengthen that organ; and a zircon set in gold was used to treat insomnia.

Zircon was also used to protect wearers from melancholia and poison, and relieve indigestion and jaundice. Contrarily, zircon was thought to cause miscarriage if worn by pregnant women.

Stones should be stored separately from other jewellery. Wearers should also be aware that prolonged exposure to sunlight can alter the colour of the gemstone.

fact sheet

Zircon
Hardness: 7 - 7.5
Variety of: silicate of zirconium
Found: Sri Lanka, Pakistan, Burma, Vietnam, Thailand, South-West Africa, France, Norway, USA, Canada and Australia.