- Category: Gemstones by the Month
Opal: October's gemstone
What is opal?
All of Nature’s fury can be seen in fine opal. Like a Rembrandt: fire, lightning, all the colours of the rainbow and the far seas. Opal is composed of silica and water, and is non-crystalline. Formed over millions of years as water passing through sandstone picks up tiny particles of silica.
The Australia outback supplies about 95% of all opal. Aborigines there believe their creator came on a rainbow to bring peace - at the spot where he landed, opal was born! In Greek, the word “opallios”, translates as “colour change” - and to the ancient Romans “opalus”, was a stone from several elements.
Types of opal
Fine opals shine and sparkle in a continually changing play of colours called “opalising”. Most opal has this play of colours except “common opal”, a name give to all others, like Pink Opal. Fine opalising opal is very expensive with individual beads going for hundreds of US dollars. Therefore, the type of opal common in necklaces is non-opalising opal – usually pink opal from Peru.
How it works
Opal’s fantasy-like play of colour is caused by small spheres of silica refracting the light inside the host stone. These spheres ensure the rainbow effect is always new and different.
How to value opal
The most important factor in the price of fine opal is the play of colour, the colours themselves, and their pattern. If red appears when looking through the stone, all the other colours will also. Value also depends on body colour, transparency, and original location. Body colour can be black, dark or light, or collared. Black Opal has the most brilliant play of colour – and these from Lightning Ridge or Mexican Fire are the best. Crystal opal is the next preferred, and should be more transparent. White or milky opals show more diffuse colour and are the cheapest.
To bring out the play of colour, the stones are cut and polished to a softly domed shape, like oval cabochons. Only the best fire opal is suited to faceting. The opal cutter removes any impurities using a diamond cutting wheel - before working the basic shape, fine cutting, and smoothing with sandpaper and polishing with a wet leather wheel.
How does opal affect you?
Opal is thought to cure depression and to help its wearer find true love. Opals are supposed to enhance the positive characteristics for people born under the sign of Cancer. The opalising effect reflects changing emotions and moods. Opals are like human emotions: each type creates different feeling.
Peruvian opal comes in faint-pink, light-blue and light mint-green tones - from the Andes Mountains, Peru. Although native South Americans have been using the stone for more than a thousand years, it only became widely available commercially within the last decade or so.
Peruvian opal is usually translucent to opaque with no play of colour and often has lots of black and tan dendrites. Most Peruvian opal beads are semi-opaque to opaque.
Peruvian opal’s metaphysical properties are similar to other opals. Helping to intensify your traits and characteristics and deepening your personal understanding. Peruvian Opal in particular is used to activate the heart charka and to assist you during spiritual journeys.
Looking after opal
Due to 2 to 6% water, opals easily becomes brittle and if stored too dry or exposed to heat for too long, they perish and the play of colour fades. Therefore, opal jewellery should be worn as often as possible – giving the gemstone humidity from the air and skin of its wearer. Years ago, opal’s sensitive surface was oiled, but today they are sealed with clear resin.