On Friday June 6th, a separate workshop on Reference Material Development for Common-Pb-Mineral U-Th-Pb Geochronology (https://www.nawlaworkshop.com/geochron-friday) will be held at The University of Tennessee. It will be hosted by Paul Sylvester (Texas Tech Univ) and Kate Souders (USGS/Denver) and sponsored by an award from the AGeS3-TRaCE program supported by the National Science Foundation. Contributed oral and poster presentations documenting promising reference materials are encouraged. The convenors will contact potential presenters to discuss follow-up details to build the workshop program beginning April 21st.