Coloured Gemstones and factors that affect their value

Delivered by Amanda Good FGA Dia.Dip. 23rd February 2018


For those who were lucky enough to attend this one-day fully hands-on coloured gemstone workshop in London last month, what a treat this was.

We met at Leather Lane meeting rooms with Amanda Good for an outstanding day covering all aspects of the most popular coloured gemstones, The day was split into theory in the morning and hands on examining and looking at pricing and handling gemstone samples in the afternoon. Amanda currently works at G F Williams and has previously worked at Thomson Gems as their gemstone buyer. She spent many years living in Sri Lanka and travelling the world in search of coloured gemstones and a has huge  wealth of knowledge in the coloured gemstone field and was more than happy to share this with all people during the course of the day.


The day was an in depth look into what affects prices of coloured gemstones with more than 50 samples to examine and  price, kindly loaned by G F Williams. Amanda discussed up to date changes in the world, market forces and what is driving prices.

The morning session covered current colour grading systems, cut, colour and clarity, and importantly what affects the value of gemstones. Origins and treatments were discussed along with cutting centres and production around the world.

Lunchtime gave us the chance to catch up with friends and acquaintances over a buffet style lunch in a relaxed setting.


In the afternoon we worked as small groups, four or five to a table, handling all the samples which Amanda had brought and having a go at identifying and pricing them. This for me was the most important and significant part of the day as the samples were in gemstone order, with 5 or 6 samples in each gem category with carat prices ranging from a few pounds per carat to a few thousand pounds per carat. There were a few red herrings thrown in, just to test us. We primarily looked at Ruby, Sapphire, Emerald, Tanzanite, Aquamarine and Tourmaline, all the key gemstones, but Amanda also brought in a huge selection of other stones, both rough and cut for examination and discussion.

We were then able to spend time looking at the pricing of the samples and left the day with handouts and even some samples of treated/ composite ruby and sapphire, kindly donated by Shirley.


This was an outstanding workshop day, focusing on issues which valuers and retailers face every day, definitely one not to miss if the workshop is run again.


Georgina Deer FGA DGA FIRV

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