FactSheet – Opal

Origin
Opals form very slowly in sedimentary rocks (e.g. sandstone) where water is present.

Composition: Hydrated silica: SiO2·n(H2O)
Structure: No crystal structure, instead a regular arrangement of miniscule silica spheres which diffract, or scatter, light. Variations in sphere size determine the range of colours seen.
Colours: More precious opals all show some internal ‘colour play’ or ‘flashes’. Blue/green opals are very popular but those containing reds, oranges or violets usually demand a premium.
‘Fire opals’ refer to red/orange clear opals (NOT from the internal flashes mentioned above).

Sources
Crystals buys its range of opals from the extremely hot, dry centre of Australia where the opal miners not only extract opal underground, their houses are also underground!

History
Shakespeare referred to opal as ‘the queen of gems’ in Twelfth Night.
Pliny, in Roman times, described opal as having ‘the fire of the carbuncle, the brilliant purple of the amethyst, and the sea-green of the emerald, all shining together in incredible union’.
The Arabs believed opals fell from heaven in flashes of lightning, gaining their fiery flashes as they fell.

Our view...
Opals can be somewhat controversial – even unlucky? This idea has come about from people not knowing how to look after opal stones (see below). We find opals are beautiful, inspirational and suited to everyone! Obviously their properties may result in careless owners suffering damage – a natural consequence of their own behaviour NOT opals being unlucky. It is also said that the opal cutters were always the poorest of the stone cutters as opals are easy to damage during cutting (so the cutters’ profits would be lost).


How to care for opals:
The particular characteristics of opals mean that certain rules must be followed to keep the stones in good condition:

• Avoid scratching the relatively soft surface.

• Avoid very high temperatures (e.g. very hot water) or extreme low humidity (e.g., bank vaults!).

• Clean, if necessary, with mild detergent and a damp cloth or soft toothbrush.

• If storing for long periods, pop in cotton wool in a sealed plastic bag with a few drops of water.

Ros Mason – April 2006
© Crystals (UK) Ltd. T/A Crystals Reg. No. 5056864.

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Birthstones
& Zodiac stones
Our choices of stones are an amalgamation of modern and traditional systems, as well as those originating from Roman, Hebrew and Ayurvedic sources. We hope you find them useful.

•
Birthstones

January – Garnet
(also Rose Quartz)

February – Amethyst
(also Onyx)

March – Aquamarine
(also Bloodstone, Red Jasper)

April – Diamond
(also Rock Crystal/Quartz)

May – Emerald
(also Agate, Chrysoprase)

June – Moonstone
(also Pearl, Alexandrite)

July – Ruby
(also Jade, Carnelian)

August – Peridot
(also Carnelian, Sardonyx)

September – Sapphire
(also Chrysolite, Lapis Lazuli)

October – Opal
(also Beryl, Pink Tourmaline)

November – Yellow Topaz
(also Citrine)

December – Turquoise
(also Blue Topaz)

•
Zodiac Stones

Aquarius – Garnet

Pisces – Amethyst

Aries – Bloodstone

Taurus – Sapphire

Gemini – Agate

Cancer – Emerald

Leo – Onyx

Virgo – Carnelian

Libra – Chrysolite

Scorpio – Beryl

Sagittarius – Topaz

Capricorn – Ruby
Crystals (UK) Ltd.
Head Office: 13 Norman Court, Budlake Rd, Marsh Barton
Exeter EX2 8PY, UK
www.crystalshop.co.uk