We said if you just pick up a rock, it is probably chert. How does this pervasive rock form? I mean we should have a good idea, right?Fun Paper FridayTime for tea and biscuits... and science.Jones, Ceri, and John Francis. "Direct Uptake of Nutrition and Caffeine Study (DUNCS): biscuit based comparative study." bmj 379 (2022). (https://www.bmj.com/content/379/bmj-2022-072839)Contact us:ShowSupport us on Patreon! (https://www.patreon.com/dontpanicgeo)www.dontpanicgeocast.com (http://www.dontpanicgeocast.com)@dontpanicgeo (https://twitter.com/dontpanicgeo)show@dontpanicgeocast.comJohn Leeman- www.johnrleeman.com (http://www.johnrleeman.com)- @geo_leeman (https://twitter.com/geo_leeman)Shannon Dulin- @ShannonDulin (https://twitter.com/ShannonDulin)