3 Photos
Massicot
Chemical Formula	PbO
Species	Oxides & Hydroxides
Crystal System	Orthorhombic
Mohs Scale	2
Specific Gravity	9.64
Color	Sulphur- to orpiment-yellow, sometimes with a reddish tint. Nearly colourless to pale yellow in transmitted light.
Streak	Yellow
Luster	Greasy, Dull
Refractive Index	n = 2.510 n = 2.610 n = 2.710
Crystal Habit：Massive, earthy to scaly. Artificial crystals are tabular .
Geological Setting：As an alteration product of lead minerals.

Massicot is one of the natural mineral forms of lead(II) oxide, PbO. Massicot is the orthorhombic dimorph of the tetragonal form of lead oxide, litharge. It forms soft (Mohs hardness of 2) yellow to reddish-yellow, earthy, scaley masses which are very dense, with a specific gravity of 9.64.

It was first described in 1841 for an occurrence in Stolberg, near Aachen, Germany. Massicot is French for "lead oxide".