The opal is an amorphous mineraloid gel SiO2ĚnH2O (hydrated silicon dioxide) which is deposited at relatively low temperature. Opal can be clear white, gray, red, yellow, green, shore, blue, magenta, brown, and black. Of these hues, red and black are the rarest and therefore the most expensive. White and green are the most common. Common opal is amorphous, but precious opal does have a structural element. The word opal comes from the Latin opalus. The Opals is Australia's national gemstone and as a consequence is a good idea for a souvenir.
The quality and value of a solid Black Opal is governed by a number of factors:
- Brilliance or Lustre
- Colour Background
- Spectral Colour Range
- Colour Pattern
- Face Up Display
- Stone Size
You can find three types of stones:
- Solid opal in its natural form is cut and polished.
- Doublets are made from a layer of translucent opal, which is adhered to a black base to increase the contrast of the colours.
- Triplets are made of a thin layer of opal that has been enhanced on the base same as a doublet but has also an artificial dome on the top that can be made of glass, crystal or plastic.
Warning: If you don't know how to identify the opal stones do not buy from any shop because you can buy a cheap fake at a high price. Look for a reputable shop.
tourist information ...
How to get there
Opposite 'Galeries Victoria' Monorail
Level 3, 295 Pitt Street, Sydney 2000
Phone: (02) 9261 2442
Web site: Australian Opal Cutters
Hours of Operation