How to identify Galena

To correctly identify Galena (Lead Sulfide (PbS)), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Lead-gray to silvery-gray, often tarnishing to a dull gray or iridescent blue/purple.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Bright metallic on fresh surfaces, becoming duller with tarnish.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Typically granular or massive, but can exhibit well-formed cubic or cubo-octahedral crystals with smooth, reflective faces.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cubic, cubo-octahedral, or octahedral crystals are common. Also found as massive, granular, or fibrous aggregates.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Perfect cubic cleavage in three directions at 90 degrees, producing characteristic step-like fractures or perfect cubes when broken.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Hydrothermal veins, replacement deposits in limestones and dolomites, and less commonly in sedimentary and contact metamorphic deposits. Often associated with sphalerite, pyrite, chalcopyrite, quartz, calcite, and fluorite.

Key Facts

Hardness

2.5-2.75 on the Mohs scale

Specific Gravity

7.4-7.6 (exceptionally heavy)

Crystal System

Isometric (cubic)

Color

Lead-gray to silvery-gray, often tarnished

Luster

Metallic

Transparency

Opaque

Fracture

Subconchoidal to uneven, but rarely observed due to perfect cleavage

Cleavage

Perfect cubic (three directions at 90 degrees)

Composition

Lead sulfide (PbS), often with minor silver (Ag), bismuth (Bi), antimony (Sb), and zinc (Zn) impurities.

Physical characteristics

• Crystal Habit: Cubic, cubo-octahedral, octahedral; also massive, granular, fibrous.
• Cleavage Type: Perfect cubic {001}
• Fracture Type: Subconchoidal to uneven (rarely seen due to cleavage)
• Tenacity: Brittle
• Luster Type: Metallic

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