How to identify Galena

To correctly identify Galena (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.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Bright metallic, especially on fresh surfaces. Tarnished surfaces may appear dull.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Typically massive, granular, or as well-formed cubic or cubo-octahedral crystals. Can be fine-grained to coarse-grained.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cubic, cubo-octahedral, or octahedral crystals are common. Also occurs as massive, granular, or rarely 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 breaking into perfect cubes.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Hydrothermal veins (mesothermal to epithermal), Mississippi Valley-type (MVT) deposits, sedimentary exhalative (SEDEX) deposits, and contact metamorphic deposits. Often found in association with sphalerite, chalcopyrite, pyrite, fluorite, barite, quartz, and calcite.

Key Facts

Hardness

2.5-2.75 on the Mohs scale (relatively soft)

Specific Gravity

7.4-7.6 g/cm³ (very heavy)

Crystal System

Isometric (cubic)

Color

Lead-gray to silvery-gray, often tarnishing dull gray

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 silver (Ag), bismuth (Bi), antimony (Sb), and zinc (Zn) as impurities.

Physical characteristics

• Crystal Habit: Cubic, cubo-octahedral, octahedral, massive, granular, rarely 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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