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Notes: all test samples shown are blended at 73% clay, 12% C&C ball clay, and 15% mahavir potash as a baseline: fired in oxidation. Red body is a generic term used to describe iron bearing clays that have a red hue. There are other iron bearing clays that can present as green, grey, and black; these are exceptions, not the rule for commercial bodies. The three iron sources found in natural clay are hematite, magnetite, and iron disulfide. Iron disulfide is the common iron source in the USA and Canada; however hematite and magnetite are included because they are sourced in other countries. Hematite and magnetite are also harvested by local potters in North America. Typical iron bearing clays average between 5.0 to 8.4% of iron by weight. The tile graph below shows unglazed red bodied clays, with a locally sourced magnetite ( dark gray) sample from NY. (TY Mary) All five fire to a traditional Tera Cotta at cone 04; although there is some variance in color depth. At cone 3, enough heat is present to cause some reduction resulting in color shifts. At cone 6; iron disulfide typically turns a deep brown; magnetite is nearly black; while hematite maintains a Terra Cotta color pending alumina levels, or a deep reddish brown. The note below identifies the labels for each clay; as well as their iron source. Additional Test Note: IM (IMCO Burgundy), and RA (Red Art) contains iron disulfide as the primary iron source. Newman Red (N) is a blended material that incorporates primarily hematite. H (hematite) is a locally sourced material that is not commercially available. Magnetite (M) is also locally sourced and not available commercially. Nerd