Galena

Galena
Galena with minor pyrite
General
Category	Sulfide mineral
Formula	PbS
IMA symbol	Gn[1]
Strunz classification	2.CD.10
Dana classification	2.8.1.1
Crystal system	Cubic
Crystal class	Hexoctahedral (m3m) H–M symbol: (⁠4/m⁠ 3 ⁠2/m⁠)
Space group	Fm3m
Unit cell	a = 5.936 Å; Z = 4
Identification
Color	Lead gray and silvery
Crystal habit	Cubes and octahedra, blocky, tabular and sometimes skeletal crystals
Twinning	Contact, penetration and lamellar
Cleavage	Cubic perfect on {001}, parting on {111}
Fracture	Subconchoidal
Tenacity	Brittle
Mohs scale hardness	2.5–2.75
Luster	Metallic on cleavage planes
Streak	Lead gray
Diaphaneity	Opaque
Specific gravity	7.2–7.6
Optical properties	Isotropic and opaque
Fusibility	2
Other characteristics	Natural semiconductor
References	[2][3][4]

Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver.^[5]

Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite.

As a pure specimen held in the hand, under standard temperature and pressure, galena is insoluble in water and so is almost non-toxic. Handling galena under these specific conditions (such as in a museum or as part of geology instruction) poses practically no risk; however, as lead(II) sulfide is reasonably reactive in a variety of environments, it can be highly toxic if swallowed or inhaled, particularly under prolonged or repeated exposure.^[6]