The 9th International Conference on Mineralogy and Museums (MM9) scheduled for 5-7 July 2020, will be held 24-26 August 2021 at the National Museum “Earth and Man” in Sofia, Bulgaria. It is organized by the International Mineralogical Association’s Commission on Museums. It will be a hybrid type scientific conference with both "live" in-person events and an online component. Online registration<https://events.cmebg.com/mm9/203/> is now open and the deadline for early registration and extended abstract submission is 10 May 2021. We highly encourage potential participants to submit an abstract for an oral or poster presentation before this deadline. More information on MM9 can be found on our conference website<https://events.cmebg.com/files/files/MM9website2021(1).pdf>, as well as on the IMA website<https://www.ima-mineralogy.org/>. Feel free to inform other colleagues. The program for the conference remains the same. The four sessions (oral and/or poster presentations) are: Session 1 - Mineralogical research and museums; Session 2 - Archaeological mineralogy and cultural heritage; Session 3 - Collection management and development; Session 4 - Museums, environment and society. Looking forward to meeting you in Sofia! Kind regards, Ruslan I. Kostov Chair, MM9 National Organizing Committee ------- Prof. Ruslan I. Kostov, PhD, DSc Bulgarian Mineralogical Society Acad. G. Bonchev Str., Bl. 24 Sofia 1113 Bulgaria