How to identify Serpentinite

To correctly identify Serpentinite (Serpentinite), 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

   Typically shades of green (dark green, olive green, yellowish-green), often mottled, spotted, or veined with black, white, or reddish-brown.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Greasy, waxy, silky (especially chrysotile varieties), or dull.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, slippery, or scaly to fibrous. Can be massive, platy, or fibrous.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Individual serpentine minerals are typically microscopic. The rock itself is massive, platy, or fibrous. Pseudomorphs after olivine or pyroxene may be visible.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Serpentine minerals exhibit perfect cleavage in one direction (basal), but in the massive rock, it's rarely observed. Instead, the rock tends to fracture irregularly or splinter.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Associated with ophiolite complexes, subduction zones, and areas where ultramafic rocks have undergone hydrothermal alteration. Often found in mountain belts and along major fault zones.

Key Facts

Hardness

2.5-4 (Mohs scale)

Specific Gravity

2.5-2.9 g/cm³

Crystal System

Monoclinic (antigorite, chrysotile), Orthorhombic (lizardite)

Color

Various shades of green, often mottled or veined

Luster

Greasy, waxy, silky, dull

Transparency

Translucent to opaque

Fracture

Conchoidal, splintery, or uneven

Cleavage

Perfect basal cleavage in individual serpentine minerals, but rarely observed in the massive rock

Composition

Hydrous magnesium silicate, Mg₃Si₂O₅(OH)₄

Physical characteristics

• Crystal Habit: Massive, platy, fibrous (chrysotile), or pseudomorphic after original minerals.
• Cleavage Type: Not typically observed as rock cleavage; individual minerals have perfect basal cleavage.
• Fracture Type: Conchoidal, splintery, or uneven.
• Tenacity: Brittle to tough.
• Luster Type: Greasy, waxy, silky, dull.

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