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New technology for grading Opal

Opals Down Under News

The latest news from your favourite opal shop.

New technology for grading Opal

Fri 20 Nov, 2009

There has been news lately of a development from the CSIRO and O.P.A.L. (Opal Producers Australia Limited), where they have unveiled the world's first automated device to grade opals using image analysis. Due to Opals having such a vast, unique range of colour characteristics, they are by far the most difficult gemstone to appraise, with certain qualities such as 'flash' can vary with human eyesight and lighting conditions. The reason behind this development, according to the CSIRO and O.P.A.L., is that judging opal on all of its characteristics is a difficult task, even for the most skilled opal assessor, and the group believes that the industry needs image analysis and automation to fully assist with the grading and pricing of precious opal. Basically, the group have incorporated the expert knowledge of over 60 opal industry professionals and then designed a GDA prototype with an Australian company called Applied Robotics. Complex mathematical algorithms were then developed by CSIRO to drive the image analysis system behind the GDA. It's all very complex, with a small camera taking 871 images of the stone as it rotates on a stage which moves 360 degrees horizontally and tilts 90 degrees vertically. The images are then analysed by high-powered computers linked to the GDA, which quantify the opal's gemmological characteristics, providing a classification grade (this is based on colour, clarity, carat, cut and character), and a summary graph is produced showing the proportions of the opal's colours. Simply, the GDA helps to give a more balanced grading method, thus providing a more even dollar value to particular grades of stones, depending on the daily market price. The product, branded as Opallia, aims to give miners a fair price for the opal, and provide consumers more confidence to trade with grade quality assurance. While we agree with the concept of a unified grading system for Opal, Scott (our Opal Cutter and Manager here with 20 years experience in the industry) has some concerns about the practicallity of the system, how accessible it will be, who originally set the prices within the program and how do they monitor the fluctuating prices of opal on a monthly basis? Also, he is concerned that the group that has developed the system haven't taken into consideration the time that this will take, considering that if you base their idea on analysing gem-grade opals (so basically anything over AU$1,000), there will be 10's of thousands of these stones to grade on a yearly basis. Also, the cost of the machine is a concern, particularly for private opal companies, which could work out to be a huge outlay. We have tried to contact the group via the website, but with no success, and we are also unsure when the 'Opallia' system will be commercially available.
Mike says: This has become an important issue recently, as one of the leading opal auction sites has suggested to its members that they will be changing to a grading system which incorporates this technology and the arbitrary standards which they will set. Who are these 60 leading experts? What does this mean to other source countries? Many questions abound...Mike Kelley
Mon 17 May 2010