Reynolds Cup 2024 Registration


Excel file for results can be downloaded here

Dear Clay-friends, (and in this we include anyone interested in quantitative mineralogical analysis of samples that may contain clay minerals!)

The 2024 (12th) biennial Reynolds Cup competition on quantitative mineralogical analysis is open for registration.

The competition is open to anyone interested in quantitative mineral analysis, with particular emphasis on clay mineralogy. Information about the competition including guidelines and previous winners can be found at The competition is free for all to enter, however, those who are not members of the CMS are encouraged (but not obliged) to become members (see

A total of ~100 sets of samples will be made available for distribution. Each set will comprise three samples of ~3–4 g of mineral mixtures commonly found in clay-bearing rocks. All sets of samples will be distributed in the order of registration.

The winner(s) and participants who finish in the top three places will be announced. The names of the other participants will remain strictly confidential. Note – due to some delays with shipping samples the deadline for submitting results and the date and venue for announcing the results is still to be decided.

Because of the popularity of the Reynolds Cup and the enormous amount of work put into its preparation, potential participants are strongly encouraged to plan ahead and only request samples if they are sure they can complete the analysis and return results to the organizers by the due date. Those who request samples and do not send in results or fail to return the samples unopened WELL BEFORE the due date will not be eligible to participate in future Reynolds Cups. A waiting list will be kept to offer returned samples to other potential participants.

The Reynolds Cup, blind Round Robin is the perfect way (possibly the only way!) to test the ability and accuracy of your methods of quantitative mineralogical analysis, whatever your prefered method or technique, so join the fun and participate.

Reynolds Cup 2024 organizers