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What is an opal?

Opal is a precious gem first used by the Romans.  The name Opal is thought to mean, "Play of colour", which describes the way the gem's brilliant fire-like colours vary when it is tilted.  Opals can contain any colour found in the rainbow, this is because the colour releases when the light passes through tiny spheres of silica and the voids between them, created within the stone.

Different types of opal

Potch or common opal is opal but with no "colour", it can be clear, milky, grey or black and on its own, it is of little value.

    Black opal Colour on or in black potch.
    Semi-black opal Colour on or in grey potch.
    Crystal opal Colour in clear potch.
    Milky opal Colour on or in white potch.
    Boulder opal Colour on ironstone, Mixed in with the ironstone or as a thin layer on top.

The most vibrant colour is found where the colour is in a crystal colour bar on black potch as opposed to colour being in the black potch, which is the difference between "on or in". Each opal is completely individual, and although many have tried to synthesise the opal's properties, there have been no imitations that truly reflect the deep beauty found in the real gem.  The closest "un-natural" jewellery stones to real black opal are the doublets and triplets.  This as their name suggests is a thin layer of real opal colour, (normally crystal) with some backing material.  On the better quality doublets natural black potch is used, other materials used for backings include ironstone and black plastic.  The triplet has a quartz cap glued on top to protect the even thinner fragile layer of opal colour.  If your budget is limited then they make a nice cheap present much the same as gold plated jewellery can.

In the UK today, black opal is unknown to most people (and sadly some jewellers) as a precious gem. Generally, when people think of opal they are thinking of milky opal, which although attractive, is nothing compared to the colour, brightness or value of black opal.

The background of opals

Shakespeare referred to opal as the "Queen of Gems" in his play "Twelfth Night".  Opal is included among the noble gems worn by Kings and Queens throughout history, and was much loved by Queen Victoria.

Opals have been the subject of many folklore tales.  They have been called both lucky, and unlucky to the wearer.  Of course there is no evidence an opal can improve luck, health, wealth or even eyesight.  It is unlucky for those who can not afford them because they miss being able to gaze at the most beautiful gem in the world!  That is of course unless you let them look at yours.

Unlike the gold and diamond trade, there is no huge stockpile of opals, and there are no large companies controlling the market.  Therefore, opal prices change to reflect the current demand.  In a report done by J.J.Watkins of the Department of Mineral Resources (NSW) in November 1984 it was estimated that there was only another 50 years of black opal mining left before the worlds only reliable know black opal fields become mined out so that leaves about 30 years, but people have been saying the same about oil and time is telling a different story.  Because Opal is such an elusive gem it would be very hard to guess when the last opals will be mined it could even be sooner.

How are they valued?

Opal just as any precious gem has a PPC Price Per Carat value, which when multiplied by the weight gives the value of the gem.  For example if a gems weight was 0.5 of a carat (5 Carats = 1 Gram) and the PPC was £100(GBP) then the price of the gem would be (£100 X 0.5) £50(GBP).

Currently black opal is the most expensive type of opal, and the rarest colour is red (on black) which makes it the most expensive.  The reason red is so rare is because the silica spheres have to be packed and aligned perfectly. As the spheres differ is size or spacing the more common colours are achieved. The price comes down as you go through the colours of the rainbow until you get to Purple, which is the most common colour in opal.  Colour is not the only factor governing the value, it is also determined by looking at the pattern, brilliance and clarity of the colour, as well as the size, shape and quality of the stone.

Prices vary greatly, and weight for weight the better black opal have exceeded the value of a good quality diamonds and we believe for good reasons.

Because there is so much demand for black opal in the USA, we show an estimated USD United States Dollars price which we provide only as a guide.  The actual price you would pay if you have a currency other than GBP Great British Pounds would depend on your method of payment and the currency exchange rate at the time.  For a more accurate price in a currency other than GBP, please contact your bank.

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