Eric Walker added Antimony - Wikipedia and The Romans Called it ‘Alexandrian Glass.’ Where Was It Really From? - The New York Times to Antimony, and added Antimony to Metalloids and Chemical elements

Eric Walker added Antimony and Silicon to Metalloids, and added Metalloids to Atoms, molecules, chemicals, minerals, materials and compounds

Eric Walker added a number of topics and a number of links to Atoms, molecules, chemicals, minerals, materials and compounds, and added Atoms, molecules, chemicals, minerals, materials and compounds to Nature

Eric Walker added Silicon dioxide and Silicates to Silicon, and added Silicon to Metalloids and Chemical elements