Opal Value-


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.




If you would like to find out the value of your Opal, bring it to Australian Opal Cutters! We have extensive experience in cutting Opals for over 35 years, and use an industry standard program called 'Smart Chart'  to value any natural Opals with a detailed and systematic approach.

This "industry leading" program assesses the essential characteristics of an Opal to determine its value. These characteristics include:  Variety, Body Tones, Brightness, Transparency, Colour, Hue, Outline, Profile, Pattern, Display, Distribution, Inclusions and Weight.

We recommend having your Opals valued every few years as fine quality Opal will increase in value each year as much as 15%.

Written valuations are available for $125 for each loose Opal.

The Diamond industry has developed a robust valuation model for Diamonds. Most gem valuers have been trained to carefully assess the "4 C's" or the Cut, Colour, Clarity and Carat weight. Unfortunately these values are only 4 of the 14 categories that need to be assessed in order to finalize the value and (unfortunately) when you use a Diamond valuer to valuer an Opal the result is unreliable.

If you are looking to make a purchase, or investigating a family heirloom then these characteristics are a simplified method to give you some confidence. These would be the 3 most important factors if you are looking to make a purchase or get a basic idea of the value. Opal value is ultimately all about the colour, brightness and pattern.


 Is best when multi-directional. You should be able to see different colours from variety of angles. Spin the gemstone around to see how many colours in the spectrum you can see. As a general rule if you can see pink or aqua you will generally be able to see all of the colours of the spectrum at some point. It is important to note that Opal colour can show completely different spectral colour bands in different 'types' of light. So try looking at the Opal in daylight (sunlight), UV light, with a torch as you may see completely different colours revealed and this adds value!


Intense, brilliant colour is more valuable. High quality Opal will show you colour without direct light. We call this the 'miners test'.Simply take your Opal out of the bright showroom or sunlight and hold the Opal 'cupped' in your hand creating a shadow. Opals with `gem quality' colour will show intense flashes or display this colour even out of the direct light.


Patterns occur when the array of molecules are perfectly aligned in repeated sequences (blocks of molecules with the same structure). It is staggeringly rare and makes up only 0.01% of all Opals. Opals with ‘named’ patterns are far more valuable than regular Opals as they are so much rarer. This possibly accounts for the greatest confusion in the Opal industry as there may be two Opals side-by-side that look ‘basically the same’ (to a novice) yet one has a ‘named pattern’ which increases the value exponentially.Patterns such as ‘pinfire' , ‘chaff’, ‘straw’, ‘sheen’, ‘feather’ to name just a few and, when you find large blocks of colour you have the elusive ‘Harlequin’ pattern, the #1 most valuable commercially available gemstone in the world. To give you an idea of the rarity of this pattern we have cut and traded literally millions of Opals in over 60 years and have seen less than 10 genuine Harlequin patterned Opals. One Miners that we work with has been mining for 20 years and has never uncovered a harlequin patterned Opal.

Be cautious of anyone who tries to tell you what your Opal is worth without first assessing the 13 characteristics of the Opal. Opal is in the TOP 10 most valuable gemstones in the world, so be sure to ask your valuer: "How many characteristics do you look at when valuing an Opal?" or ask which valuation program your valuer has used to assess value, or which certification they have done to qualify them to value and Opal.

Most importantly, once your valuer has determined the value ask: do you have any comparable examples for this value? Where could I see them? This question is important as valuers have been known to ‘google’ the value of an Opal by simply entering in the characteristics into a search and then using the result to define a value.

The problem with this is in the integrity of the search results (or lack of). It is a huge problem online that many thousands of tens of Opals that are advertised as "Australian" or "Natural" Opal are actually synthetic Opal,(a complex plastic) or Ethiopian Opal (which is regularly dyed, heated and treated) which is far less valueable than Australian Opal but looks exactly the same.

If it is just an "opinion" of value and does not answer the above characteristics it is basically not worth considering.

So please contact Australian Opal Cutters to find out the TRUE value of your Opal!


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” / descriptive naming system) for OpaI is considered a key in establishing the correct value for the various types of Opal. For example, when a customer buys a Black Opal at some expense they need to be confident that is indeed what is widely recognised as a “black” and not a lesser stone (White or crystal Opal).

In the example mentioned previously where International valuers have been known to confuse (or incorrectly value) Black or Boulder Opals mistaking them for Doublets this is due to the similarity of the Iron Oxide ‘bars” or Boulder Opal ironstone base (in a Boulder Opal). It is understandable as some top gem black opals actually have a flat face and can have a very straight line to differentiate the colour bar from the base tone and looks exactly like a doublet (but is not). It is understandable that diamond valuers could even confuse the actual “types” of Opal (which can affect value dramatically) as there are so many elements involved.

Over the past few years the Gemmological Association of Australia (GAA) has worked at developing a defining nomenclature. The Opal Association and the industry in general strongly endorses the use of these definitions with the aim of standardising nomenclature across the Opal industry worldwide.

How to best describe Opal has been a contentious and difficult issue for a very long time and may well remain so for some time to come. However, as a consequence of factors such as: growing international and local awareness of Opal as a major Australian resource; the emergence world-wide of a real desire to standardise all terminology related to gemstone and the ever growing number of synthetics and limitations that are appearing in world markets; it has become necessary to agree on some well based concepts of how a unique gem such as Opal, should be described and this has motivated the major influencers in the Australian Opal industry to work more closely together to agree on a uniform procedure and process to classify and Opal.

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, ratified and published the following standards for the Opal valuation process. The nomenclature and classification of Opal, that follows, is reproduced, verbatim, from the Resolutions of the Federal Council of the Gemmological Association of Australia.

Opal is Australia's National Gemstone. Australia produces 95% of the world's supply of precious Opal. This nomenclature encompasses all types and varieties of Opal. It provides a standardisation of terminology for the market

Opal is a gemstone consisting of hydrated amorphous silica with the chemical formula SiO2nH20. There are two basic forms of Opal described by visual appearance. "Precious Opal” is Opal which exhibits the phenomenon known as “play-of-colour”, which is produced by the diffraction of white light through a micro-structure of orderly arrayed spheres of silica. "Common Opal" (also known as "Potch") is Opal which does not exhibit a play-of-colour. The distinction between “common Opal” and “potch” is based on their formation and structure. Potch is structurally similar to precious Opal but has a disorderly arrangement of its silica spheres. Common Opal shows some degree of micro-crystalinity but as the molecules are scattered they do not form rainbows inside the Opal.

The nomenclature has not been designed to force any changes to the various colloquial terms used to describe Opal in Australia, or indeed in countries overseas such as Mexico. Colourful language, Australian colloquial terms for Opal, and terms that have been a part of the Australian scene for hundreds of years have added significantly to the mystique and folklore of everyday language used on the Opal mining fields. Expressive local terms and older historical terms always will exist in the Opal miner’s vocabulary. These will remain to have their rightful place in our

gemstone history and in the tale-telling for years to come. Terms such as “nobbies”, “semi-black”, “white-crystal”, “black-crystal”, “rubs”, “fire”, “solid”, “enhanced”, “treated”, “natural” are not referenced in the categorisation.

The purpose of the nomenclature, therefore, remains to provide a basic, yet “more official” description of the gemstone we all prize and know as Opal. This nomenclature is for everyone to use and understand. Simple descriptive terms, that can be used by the majority of people, from the customer to the scientist, have been chosen. These provide the gemstone industry as a whole with a logical and unbiased way of grading and evaluating Opal. However, simple terms do become difficult when the many different types, formations, pseudomorphic fossil replacements, mineralogical types, and geological occurrences of Australian Opal are considered.

This nomenclature aims to remove from common usage the following terms that have caused linguistic problems and confusion. These terms are ‘semi-black’, ‘grey’, and ‘solid’.

To begin with the first part of the nomenclature, mention is made of precious Opal, potch and common Opal. The best way of determining the difference between these is to observe whether or not the Opal you are viewing shows the phenomenon which we all know as play-of-colour.

It is possession of this optical phenomenon for which Opal is most prized. The differentiation between these basic forms of Opal is therefore quite simple. If the Opal displays a play-of-colour it is termed precious Opal. If a play-of-colour is not displayed, then the Opal is either common or potch Opal. While it is recognised that the term precious is neither a scientific nor gemmological term, it is retained in this nomenclature for simplicity, and with the intention of further enhancing the value of Opal as a gemstone by removing it from any historical association with ‘semi-precious’ gemstones.

In an attempt at keeping the nomenclature simple to use, the terms common Opal and potch Opal have not been separated. It must be recognised, however, that there are distinct mineralogical differences between potch and common Opal. (Jones & Segnit, 1971).

The term ‘solid’ has been removed from Opal terminology, for the simple reason that all types of Opal are essentially solid from a scientific point of view. That is, Opal does not exist naturally either as a liquid or a gas. ‘Solid’ has been replaced by the gemmological term natural Opal. Correlating with this use is the recommendation that when describing doublets and triplets that the term composite be used instead of ‘assembled’.This also is the terminology currently recommended by CIBJO.

Essentially there are three types or forms of natural Opal, which are termed simply Opal, boulder Opal and matrix Opal. Perhaps the most contentious issue in the

nomenclature concerned introduction of the term body tone, to describe the comparative lightness or darkness of an Opal as distinct from its play-of-colour. Technically, it would have been best just to have two types of ‘body tone’ — either ‘black or white’ or just ‘light or dark’. However, the sub-committee rightly decided not to attempt to change too much of the terminology that had been in common use for over a hundred years.

So, inclusion of the term black Opal was considered to be an imperative. Following much discussion the term body tone was included in the nomenclature to describe the comparative lightness or darkness of Opal — irrespective of its play-of-colour. The term tone, which is used by colour science, is in agreement with terminology used internationally to describe the lightness or darkness of particular hues or colours.

This nomenclature for Opal has been designed for use throughout the gemstone and jewellery industry, not only in Australia but internationally. While preparing this nomenclature, the sub-committee has been cognisant of conventions of international trade organisations, such as the International Confederation of Jewellery, Silverware, diamonds, pearls and stones (CIBJO), the International Coloured Gemstone Association (ICA), as well as the linguistic problems associated with different languages and the differing connotations these languages may place on an internationally acceptable nomenclature.