How to identify Galena

To correctly identify Galena (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, 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, duller on tarnished surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, often with visible cubic or octahedral crystal faces.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cubic, octahedral, or cubo-octahedral crystals are common. Also massive, granular, or fine-grained.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Perfect cubic cleavage in three directions at 90 degrees, producing characteristic stair-step fractures or breaking into perfect cubes.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Hydrothermal veins, replacement deposits in carbonate rocks, contact metamorphic deposits, and less commonly in sedimentary deposits.

Key Facts

Hardness

2.5-2.75 on the Mohs scale

Specific Gravity

7.4-7.6 (very heavy)

Crystal System

Isometric (cubic)

Color

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

Luster

Metallic

Transparency

Opaque

Fracture

Subconchoidal to uneven, but rarely observed due to perfect cleavage

Cleavage

Perfect cubic in three directions at 90 degrees

Composition

Lead sulfide (PbS), often with minor amounts of silver (Ag), bismuth (Bi), antimony (Sb), and zinc (Zn) substituting for lead.

Physical characteristics

• Crystal Habit: Cubic, octahedral, or cubo-octahedral crystals; also massive, granular, or fine-grained.
• Cleavage Type: Perfect cubic (three directions at 90 degrees)
• Fracture Type: Subconchoidal to uneven (rarely seen due to cleavage)
• Tenacity: Brittle
• Luster Type: Metallic

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