Apart from water and salt, are there any inorganic foods?
An overwhelming majority of what we eat is made from plants and animals. This means that composition of our almost entire food is chemicals from the realm of organic chemistry (carbon-based large molecules). Water and salt are two prominent examples of non-organic foodstuffs - which come from the realm of inorganic chemistry. Beside some medicines is there any more non-organic foods? Can we eat rocks, salts, metals, oxides... and I just don't know that?
Can we eat rocks, salts, metals, oxides… and I just don’t know that?
You'll die without Iron, Calcium, Potassium, Magnesium, Zinc etc. in your diet. Your body relies on a lot of metals and salts to function.
You can see an example of a food's breakdown here to see all the metals and salts involved in foods: Nutrition data for rice (make sure you scroll to the "Detailed Nutrition Data" section and expand the categories like "Minerals")
Fun fact, calcium supplements are Calcium Carbonate (CaCO3) - literally chalk. But for metals which are deliberately added to food, check out the Lucky Iron Fish developed to address anaemia in Cambodia.
I mean... it seemed like a good idea and all, but it didn't help Cambodia. It's like only a couple paragraphs down in your link. It only addresses iron-deficiency based anemia which was not the main cause of anemia in Cambodia.