Eric Walker added Pyrite to Iron sulfide, and added Iron sulfide to Sulfur, Minerals and gems and Iron

Eric Walker added a number of topics and Sulfur Hexafluoride: The Nightmare Greenhouse Gas That’s Just Too Useful To Stop Using | Hackaday to Sulfur, and added Sulfur to Chemical elements

Eric Walker added Pyrite - Wikipedia and Research Brief: ‘Fool’s gold’ may be valuable after all | University of Minnesota Twin Cities to Pyrite, and added Pyrite to Iron sulfide

Eric Walker added a number of topics and a number of links to Iron, and added Iron to Metals and Chemical elements

Eric Walker added a number of topics and a number of links to Minerals and gems, and added Minerals and gems to Geology, Natural resources and Atoms, molecules, chemicals, minerals, materials and compounds