Review... The Spectroscope and the Valuer


Half Day Workshop – Hatton Garden,  London


The spectroscope is a very useful, versatile tool in the identification of gemstones and the absorption patterns can often be diagnostic of a gems identity. It is a piece of equipment that is often overlooked by the valuer / gemmologist, maybe this is due to a lack of confidence by the user.

The workshop was presented by Claire Mitchell from Gem-A and comprised of two parts, the theory and the practical.


The theory part opened with a brief overview of the meaning of spectroscopy and a look at the electromagnetic spectrum. We then looked at the scientists whose discoveries, work and developments over several centuries from Sir Issac Newton to B.W. Anderson & C.J. Payne have led us to a point where we have the luxury of the use of a hand held spectroscope. I am always interested and fascinated by the work of the early pioneers in both science and our industry and the journey that takes place in the development of the tools that we today take for granted.

The workshop continued, covering the stones suitable for testing, the selective absorption of light, colouring elements, measurements, the types of spectroscopes, lighting sources, illumination and observation techniques. We also looked at the spectra of a selection of common gemstones and the key elements to look for, for each stone and advice on how to record the data. The comprehensive theory section was rounded off with a look at troubleshooting, available reference books, online resources and information for further study of the subject.


One of the advantages of workshops incorporating Gem-A is that they have a vast gemstone library to select from when it comes to the practical element of the workshop. Therefore when we got to the practical session there was a good selection of gemstones to test. Claire was on hand to offer expert advice on technique, lighting and results as an aid to build our confidence when using the spectroscope. It was good to know that the vague line that you were not totally sure whether you had observed or not, was actually there and confirmed by our tutor.

This was an excellent and informative workshop and whether you are a beginner, in need of a refresher or experienced in the use of the spectroscope, one that I would highly recommend. My thanks to Shirley Mitchell and The Academy of Valuers for organising the workshop and to Claire Mitchell from Gem-A for an excellent presentation and expert, hands on tuition, in the practical use of the spectroscope.


Thank you

Alan Wetherall  

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