This color contains the following pigments:
Fe2O2 or Fe2O3 • H2O
Mars Orange is a bright, extremely light red and appears almost pinkish when contrasted with darker colors. It has incredible tinting strength and opacity. The synthetic form of Mars Orange is made from iron oxides and is cleaner, brighter, and denser than its ochre-based counterparts.
Mars Orange has good permanence and lightfastness.
Mars Orange has no significant hazards.
The word Mars refers to the Roman god of iron and war. Mars Orange has been manufactured as a pigment since the 17th century.
charred animal bone
carbon + calcium phosphate
C + Ca3(PO4)2 or C × CaPO4
Ivory Black is a cool, semi-transparent blue-black with a slight brownish undertone and average tinting strength. It mixes well with any color, and creates a range of dull greens when mixed with yellow. It has good properties for use in oil, can be slow to dry in oil form, and should never be used in underpainting or frescoing. Ivory Black is denser than Lamp Black.
Ivory Black is very lightfast and has good permanence, though it is considered the least permanent of the major black pigments.
Ivory Black has no significant hazards.
Ivory Black is a carbon based black first named as Elephantium, and described in the 4th century BCE as produced by heating ivory scraps in clay pots to reduce the ivory or bone to charcoal. The deviation in names is because the more expensive varieties of this pigment were made by burning ivory, and the less expensive ones by burning animal bone. In the 19th century, the name Ivory Black was finally permitted to be applied to Carbon Black pigments made from bone. True Ivory Black is rare in modern times due to the protection of ivory, and the synthetic variety produced today was discovered in 1929. Bone Black is produced as an industrial pigment.