Galena
Image: James Petts from London, England (CC BY-SA 2.0)
Mineral NameGalena
Chemical FormulaPbS
Mohs Hardness2.5
Crystal Systemcubic
Lustermetallic
Streak Colorlead gray
Cleavageperfect cubic (three directions at 90 degrees)
Fracturesubconchoidal to uneven
Specific Gravity7.5
Colorslead-gray, silvery-gray
Transparencyopaque
Type LocalityWorldwide, notable localities include Joplin, Missouri, USA; Freiberg, Germany; and various locations in Mexico and Peru.
Mineral GroupSulfides
Usesprimary ore of lead, collector's specimens, historically as a semiconductor
Associated Mineralssphalerite, pyrite, chalcopyrite, quartz, fluorite, barite, calcite
Raritycommon
Description
This specimen displays a dark lead-gray color with a bright metallic luster, showing characteristic blocky forms due to its perfect cubic cleavage. It is partially embedded in a matrix of lighter-colored gangue minerals.
Geological Context
Galena commonly forms in hydrothermal veins, often alongside other sulfide minerals, and can also be found in sedimentary rocks as replacements or disseminations. It is a significant ore mineral in Mississippi Valley-type deposits.
