The 2026 (13th) biennial Reynolds Cup competition in quantitative mineralogical analysis is now open for registration. The event welcomes all individuals interested in quantitative mineral analysis, with a particular focus on clay mineralogy. Comprehensive guidelines and details of previous winners are available at https://clays.org/reynolds.html . Participation is free; however, non-members of The Clay Minerals Society are invited, but not required, to join (https://clays.org/join_benefits_of_membership.html ).
Approximately 100 sample sets will be distributed on a first-come, first-served basis. Only one entry per organisation is permitted. Each set contains three samples (3–4 g each) of mineral mixtures typically found in clay-bearing rocks. Participants are expected to complete the analysis and submit results by the specified deadline (to be announced). Those unable to do so must return unopened samples promptly to remain eligible for future competitions. A waiting list will be maintained for reallocated samples.
This is an Excel Spreadsheet to use to submit your results.
Results will be announced for the winner(s) and the top three participants; all other participant names will remain confidential. Please note that deadlines and result-announcement details are subject to change due to potential shipping delays.
The Reynolds Cup offers a unique opportunity to objectively assess the accuracy of your quantitative mineralogical analysis methods. We encourage all interested parties to participate.
Reynolds Cup 2026 Organisers