Striking Northern Territory Opals
The northern territory opals found in the Lightening Ridge opal mines are world famous. The only place in the world where black opals are produced is in the Lightening Ridge opal mining fields. The black opal unlike ordinary opals has carbon and iron oxide trace elements in it making it the most sought after opal.
Opal is an amorphous non-crystalline gem mineral that is solidified from gelatinous or liquid silica which is deposited in the cracks and cavities left by decaying wood, vegetation, bones and crustaceans. It is very valuable in its black form and contains a reasonable of water.
Early cultures throughout history have credited opal with magical properties, since it is believed to possess the healing properties of all the gemstones, because of its multitude of colors.
To the aborigines who believe that they have lived in Australia since the Dreamtime - the beginning of all creation, opals like other minerals have a spiritual significance since they represent something a Dreaming ancestor had left behind as a sign of presence.
Opal is the national gemstone of Australia, currently around 95% of the world's opals that is used in the manufacture of jewelry is produced in Australia. The main fields of Australia are found in Queensland, New South Wales, and South Australia.
Though there are various types of opals present in nature, there are however two main varieties; the common opal or potch and the precious opal. The opals which are dull and valueless are called the common opals and they occur in abundance throughout the world. It is when the common opal is found in association with precious opal, it is known as potch. Precious opals called opaline silica with a 'play of light' (the term is used to describe the opal's beautiful shifting of spectral hues). Australian opals because they are hosted predominately by sedimentary rocks of the Mesozoic Great Artesian Basin are referred to as sedimentary opals.
Opals are technically considered mineraloid since it is amorphous. Mineraloids are like minerals in nature however, they lack crystal structures. The appearance of the opal can be colorless, white, yellow, blue, green brown and black. They can however portray all these colors in combination. This brilliant combination of colors is what makes the opal a valuable gemstone. The common kinds of opals are those that are white and light blue. Colored opals like orange, red and violet shades are most sought after, while black opal is the rarest kind.
The unique qualities of the opal can determine the value of each individual opal which differs greatly. The main factor determining the value and price of an opal are; play of colour, body tone, colors present, pattern, brilliance and size.
Lightening Ridge opal mines have been mining and cutting opals for well over 40 years. Anything and everything you would want to know about northern territory opals can be obtained from the opal museum and showroom in the heart of Alice Springs.