A "colloid" is a chemical description of a gel-like suspension. Therefore, colloidal minerals would be a blend of minerals found in some form of suspension or solution. Generally, commercially-available colloidal minerals are produced from mining ancient sea beds, and then mixing the mined minerals with water or other fluid to hold them in solution. While these products provide a large number of minerals, there is no credible scientific evidence to support marketing claims for superior absorption or bioavailability. They may even contain relatively high levels of unwanted minerals such as aluminum, lead or mercury (which of course are naturally occurring), or of other contaminants.