Just because a miner works long hours at great expense for a low return of opal does not mean that he will get more money for it. The current market will dictate what a miner can get for their opal. A lot of miners have a misconception about this, and a buyer should not be caught out. A miner thinks that it has cost him X amount to discover a batch of opals since the last lot was mined, so he needs that as a return. So, you can find highly inflated prices because of this where a miner believes that an opal is worth much more than it is in the market because of his time and money spent in discovering it. They soon come to realize that they cannot sell at their price; and it’s not uncommon to see some opals at a quarter of the price they were originally for sale for because the miner needs money to carry on their operations. Miners are also in competition with other miners; some of whom have discovered a lot of good quality opal at the time that may drive the market lower. However most often than not, the amount of good quality opal on the market for sale is very low.
Opals are valued according to many different factors. These include brightness, body tone, density of colour, colours, patterns, size, shape, rarity of pattern (eg Harlequin). Often an opal is graded by the seller and priced at a per carat weight.

So, what are opals worth though? Opals are not graded as precisely as diamonds because every single opal is different, compared to diamonds where they are all relatively the same. Opals are worth what someone is willing to pay for them! They have also increased in value over time because discoveries have become scarce. This has happened in many, many occasions where an opal was bought for example for $1,000 20 years ago and sold recently for $50,000. If someone loves the opal, then it is worth paying the asking price. Gem opal, and especially gem black opal has such a display of different colours and patterns that no other gemstone can equal its beauty. Therefore, they hold their value increases in time. Truly good opal with very rare patterns will never decrease in value, unless of course you have overpaid for it in the initial purchase.
There was a time in 1992 however where the market witnessed a decrease in the value of opal when new fields were discovered in Lightning Ridge around Coocoran area, resulting in an oversupply of mid-grade opal.
We are asked daily by people who own opals seeking a price recommendation. Please know that we do not do appraisals. This is because it takes a substantial amount of time to price an opal for today’s market. To price an opal, look at other opals on the market of similar quality, size, shape, type, pattern, colours etc. and try to work out the price per carat. It takes us hours, sometimes even days to price a gem quality opal correctly for the market. We also need to review our prices regularly. About a third of our time in our business is spent in pricing and valuing our opals for sale to ensure we are competitive with our prices.