Crystal Galena

Chemical Formula

PbS

Composition

Lead sulfide. May contain impurities, such as silver, arsenic, antimony, and copper.

Variable Formula

(Pb,Ag,As,Sb,Cu)S

Color

Steel-gray

Streak

Steel-gray

Hardness

2.5 - 3

Crystal System

Isometric

Crystal Forms 
and Aggregates

Crystals, which may be cubes, octahedrons, or a combination of the two frequently occur. Cubes are often partially cleaved. Dodecahedrons are far less common. Also occurs massive, grainy, fibrous, platy, as veins, and as cleavage fragments.
 

Transparency

Opaque

Specific Gravity

7.4 - 7.6

Luster

Metallic. Turns somewhat dull after exposure to air.

Cleavage

1,3 - Cubic. May exhibit parting on octahedrons.

Fracture

Subconchoidal

Tenacity

Brittle

In Group

Simple Sulfides

Striking Features

Steel-gray color, extreme heaviness, and fine cleavage

Environment

In In sedimentary limestone deposits, hypothermal veins and mesothermal veins, in hydrothermalreplacement deposits, and in placer deposits. Rarely in basalts and diabase.
 

Rock Type

Igneous, Sedimentary, Metamorphic

Popularity (1-4)

1

Prevalence (1-3)

1

Demand (1-3)

1