Massicot
Description
A heavy yellow powder composed of Lead monoxide. Massicot is the name used for both the native mineral as well as the lead monoxide product made by heating lead carbonate to 300C. Litharge, another crystalline form of lead monoxide, is the oxidized product of molten lead that has been stirred or atomized to incorporate air then cooled and ground to form the yellow powder. Litharge tends to be slightly more orange than massicot due to the presence of small amounts of red lead oxide. Lead monoxide has been used as a drier in oil and as a low-fire flux in making ceramics and glass. It was also used as a yellow pigment in paints and glazes. Thin layers of lead monoxide produce iridescent colors on Brass and Bronze. It has also been used as a filler for Rubber and to produce artificial Tortoiseshell and Horn.
Synonyms and Related Terms
lead monoxide; masicote (Esp.); litargirio (Esp.); massicot (Fr.); massicote (Port.); plumbous oxide; plumbic ocher; fiallolino; giallorino; Flemish yellow; masticot; lead ocher; litharge
Risks
- Toxic by inhalation or ingestion.
- Skin contact may cause irritation or ulcers.
- Carcinogen, teratogen, suspected mutagen.
- Millipore Sigma: SDS
Physical and Chemical Properties
- Composition = PbO
- CAS = 1317-36-8
- Melting Point = 888 C
- Density = 9.40-9.53 g/ml
- Refractive Index = 2.51; 2.71; 2.61
- Soluble in acetic acid, dilute nitric acid and alkalis. Insoluble in water and ethanol.
- Turns gray on exposure to sulfur fumes.
- In transmitted PPL, the tetragonal alpha-PbO (the beta-PbO referring to massicot) form translucent particles ranging in color from pale yellow and pale yellow-orange to pale green. Some semi-opaque particles of dark reddish-brown color are also reported. Most particles are rounded in shape and other reported morphologies include square, rectangular and acicular shapes. Particles tend to agglomerate into clumps. Relief is very high and RI is greater than 1.662.
- In transmitted XPL, the particles are highly birefringent with third-order jewel tones. Extinction is straight, but clumps of particles will not show complete extinction and appear to 'twinkle' as the stage is rotated. Clumps of particles display a strong yellow body color, and smaller particles may exhibit a dull yellowish outline at extinction. Acicular particles are length-fast.
Resources and Citations
- R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966 Comment: Yellow lead monoxide has been found in sites from predynastic times in Egypt....Pliny described the preparation of both litharge and massicot....In modern times, massicot is not used as a paint pigment
- Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing) Comment: Massicot was used as an artists pigment from the 15th c. to the end of the 18th . or the early 19thc
- R.D. Harley, Artists' Pigments c. 1600-1835, Butterworth Scientific, London, 1982
- Thomas B. Brill, Light Its Interaction with Art and Antiquities, Plenum Press, New York City, 1980 Comment: Massicot is essentially absent from paintings after the thirteenth century but was used in very early times (400BC in Egypt)...
- The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996 Comment: "Pigments"
- Wikipedia: [1]Massicot (Accessed Feb. 2, 2006 and March 2025)
- Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 445
- Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985