Massicot - Encyclopedia
Class : Oxides and hydroxides
Subclass : Oxides
Crystal system : Orthorhombic
Chemistry : PbO
Rarity : Uncommon to fairly common
Massicot is a secondary mineral resulting from the alteration of primary lead minerals, notably galena. It is the dimorph of litharge. Massicot is an uncommon mineral due to its very specific formation conditions, which, like minium, require both an alkaline environment and a dry, desert to semi-desert climate. It is also found in certain industrial slags. Its name comes from the Arabic and then the Spanish mazacote meaning lead oxide. It most often occurs in masses and earthy coatings, rarely in prismatic crystals (never larger than a millimeter) with a dull to oily luster, yellow to reddish-yellow in color. With very rare exceptions, the massicot never constitutes economically exploitable concentrations.
Main photo : Massicot from Argentena Mine, Nevada, USA © Eugene & Sharon Cisneros
Massicot in the World
Twinning
Twins are known on artificial crystals.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 2
Density : 9.56
Fracture : Undetermined
Streak : Yellow
TP : Opaque to transparent
RI : 2.510 to 2.710
Birefringence : 0.200
Optical character : Biaxial +
Pleochroism : Visible
Fluorescence : None
Solubility : Nitric acid, hydrochloric acid
Magnetism : NoneRadioactivity : None