The mineral magnetite is iron oxide (Fe3O4), which is found in all three igneous, metamorphic and sedimentary rocks. This stone is often extracted from iron ore. Magnetite is also a mineral with the highest amount of iron (72.4%).

sapphire is a precious gemstone, a type of the mineral corundum, include of aluminum oxide with trace amounts of elements such as iron, titanium, chromium, vanadium, or magnesium.