1. No qualitative information is given out. Therefore participants are expected to provide both qualitative and quantitative evaluations of all the samples.

2. All analytical methods are allowed for mineral identification and quantification but the use of routine methods applied in each participant’s laboratory is encouraged.

3. A short description of the analytical procedure used must be reported together with the results.

4.Participants are encouraged to provide estimated errors of their analysis.

5. Participants are encouraged to report the phase composition in as much detail as possible even though minerals are grouped to streamline mineral names when judging. Extra information provided can be useful to break ties. The phyllosilicate/clay mineral phases will be evaluated in more detail. When returning results please use the provided spreadsheet indicating the minimum level to which the different types of (clay) minerals will be categorized f or the purposes of judging.

6. Not less than one month prior to the CMS Annual Meeting, entries are to be returned to the organizer for evaluation and judging. The judging criteria are decided by the principal organizer based on the compositions of the pure mixtures. The entry with the smallest sum of absolute errors for the three samples provided will be the winner. In the event that several entries are within established uncertainties in the compositions of the pure mineral mixtures, the principal organizer liaises with the committee to impose stricter judging criteria to select the one winner, e.g. the total clay bias, the sum of relative errors, the number of non- or misidentified phases, and more specific (clay) mineral identifications.

7. After all the entries have been returned to the organizer, the true compositions of the samples and the mineral standards are made available to the participants.

8. Prior to the CMS meeting, participants are provided with an anonymous ranking of all the results.

9. Participants who do not wish to submit results are asked to return the intact samples to the principal organizer for redistribution.

10. Any use of additionally delivered sample material will exclude the participant from ranking.

11. 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.

12. The top three finalists are announced at the CMS meeting and presented with commemorative plaques and the winner is presented with the Reynolds Cup. The cup is held by the winner until the next competition. The identities of the remaining contestants are kept confidential.