World's Most Valuable Gem
Opal is an extremely precious gem. Gem Black, Boulder, Crystal and White Opals are the world's #1 most valuable commercially available gemstone, yet they are complex with an exponentially large range of valuation characteristics than Diamonds, Rubies, Emeralds, Sapphires or Tanzanites.
You may have heard statistics being shown depicting tanzanite or other gemstones as being '1000 times rarer than diamond'; this is only suggested because there are 100 miles of tanzanite mines worldwide, and when compared to the 100,000 miles of diamond mines worldwide. However, as there is only 20 square miles of black Opal mining, Black Opal
is actually 5000 times rarer than diamond.
Opal is a diminishing resource and there is anecdotal evidence that suggests an increase of up to 25% per annum in boulder Opal prices and 15% per annum increases in white, crystal, and black Opal.
Nomenclature
To accurately define the value of an Opal it is important to work out the definitive characteristics that establish value. A small difference in (say) the body-tone (N scale) can have a big difference in the final value. Unfortunately, there are numerous anecdotal instances where international valuers have called a "Solid Opal" a "Doublet Opal" and valued the gemstone accordingly (to the detriment of the owner).
The process that is used by Australian Opal Cutters to place value on Opal has been developed through many years using the Opal valuation software known as "Smart Chart" and uses principles that have been developed by Industry representatives (Gemmological Association of Australia GAA) and associations (The Opal Association) over past decades.
The use of standardised descriptions or “Nomenclature” for OpaIs is considered a key in establishing the correct value for any type of Opal. For example, when buying a Black Opal Nomenclatures establish confidence that the gemstone is indeed “black” and not a lesser stone such as White or crystal Opal.
Recently the Gemmological Association of Australia (GAA) has worked to develop the defining nomenclature of Opals. The Opal Association, as well as the whole industry, strongly supports the usage of these standards in order to standardise nomenclature across the Opal industry globally.
As a result of reasons – such as increasing worldwide and local awareness of opal as a key Australian resource – the global emergence of a deep desire to standardise all terms linked to gemstones; and the ever-increasing number of synthetics and restrictions that are developing in world markets, opal has become a key Australian resource. It has become vital to agree on certain well-founded principles for how a unique gem like Opal should be defined, and this has prompted the key influences in the Australian Opal business to collaborate more closely to agree on a common approach and methodology for classifying and classifying Opals.
Today the Australian Gemstone Industry Council and The Gemmological Association of Australia (GAA), the Australian Gem Industry Association (AGIA), the Lightning Ridge Miners Association (LRMA), the Jewellers Association of Australia Ltd, and the Opal Association have all agreed-to, endorsed and published the following standards for the Opal valuation process. The following classification of Opal is reproduced from the Resolutions of the Federal Council of the Gemmological Association of Australia.
The nomenclature was not created with the intention of forcing modifications to the many vernacular labels used to characterise Opal in Australia, or even in other countries such as Mexico. Australian vernacular names for Opal, and phrases that have been part of the Australian landscape for hundreds of years have all contributed to the mystery and mythology of daily language used on the Opal mining fields. The Opal miner's vocabulary will always include expressive local terminology as well as older historical terminology. For years to come, they will have their appropriate position in our gemstone heritage and story-telling. Terms such as “nobbies”, “semi-black”, “white-crystal”, “black-crystal”, “rubs”, “fire”, “solid”, “enhanced”, “treated”, “natural” are not referenced in the categorisation.
As a result, the nomenclature's objective remains the same: to offer a basic, yet "official" description of the gemstone we all love and call Opal. This terminology is meant to be used and understood by everyone. Simple descriptive keywords have been used that can be understood by the majority of individuals, from the consumer to the scientist. These give a rational and fair manner of grading and appraising Opal for the whole gemstone industry. When the various distinct varieties, formations, pseudomorphic fossil replacements, mineralogical kinds, and geological occurrences of Australian Opal are studied, simple terminology becomes challenging.
Phrases such as "semi-black," "grey," and "solid" have produced language issues and misunderstanding, hence the nomenclature tries to eliminate them from regular usage.
To begin, precious Opal, potch, and common Opal are mentioned in the first section of the nomenclature. The simplest method to tell the difference between the two is to look at if the Opal you're looking at has the phenomena known as play-of-colour.
Opal is valued for its ability to produce this visual phenomenon. The distinction between these fundamental kinds of Opal is thus pretty straightforward. The Opal is classified as valuable if it has a play of colours. If there isn't a play of colour, the Opal is either common or potch Opal. While it is acknowledged that the term precious is neither a scientific nor a gemmological word, it is preserved in this nomenclature for the sake of simplicity and to further enhance the value of Opal as a gemstone by eliminating any historical relationship with ‘semi-precious' gemstones. Watch
The adjective "solid" has been dropped from Opal jargon for the simple reason that, from a scientific standpoint, all varieties of Opal are solid. That is, Opal does not exist as a liquid or a gas in nature. The gemmological word natural Opal has taken the role of the phrase "solid." The advice to use the term composite instead of "assembled" when discussing doublets and triplets corresponds to this use.
Simply said, there are three varieties or kinds of natural Opal: common Opal, boulder Opal, and matrix Opal. The inclusion of the word body tone to express the relative lightness or darkness of an Opal as opposed to its play-of-colour was perhaps the most controversial topic in the terminology. Technically, having only two sorts of "body tone" — "black or white" or "light or dark" — would have been preferable. However, the subcommittee made the correct decision not to modify too much of the nomenclature that had been in use for almost a century.
As a result, it was deemed necessary to include the word "black Opal." After much debate, the phrase "body tone" was added to the nomenclature to characterise the relative lightness or darkness of Opal, regardless of its colour play. Colour science uses the term tone, which is consistent with international language for describing the brightness or darkness of certain hues or colours.
