Iron oxide, or rust, is one way the metallic mineral, iron, occurs in nature. Limestone contains calcium. In the 1960's, chelated minerals became available. Scientist learned that by attaching an enzyme, such as an amino acid, to the clay or metallic form of a mineral they could increase the absorption rate of that mineral. Although chelated minerals are more expensive than their basic, metallic counter parts, their bioavailability is 4 to 5 times more than that of the basic mineral.
Colloids are the third category of minerals.
Colloidal minerals are different in many respects from the previously discussed minerals. Photosynthesis breaks down these raw metals into extremely fine particle form permanently suspending the minerals. These minerals are the smallest particles that matter can be divided while still retaining the vital characteristics of that substance. Colloidal minerals have enormous surface areas which gives them special properties. This, in simpler terms, means that now these various colloidal minerals can now attach themselves to many destructive positive charged free radicals and be pumped into the body's blood stream to be eliminated, as well as, performing their co-enzyme and carbohydrate metabolism functions.