What exactly is a colloidal mineral, and why is it so important? A colloid is a particle or substance that retains its identity and remains in suspension. Colloids are very small in size and therefore are easily absorbed by the cells of the body. Plants absorb metallic minerals through their roots and convert them into colloidal minerals. These plant or colloidal minerals are hydrophilic or water soluble, which is what causes them to work with, and not against, the natural body absorption processes.