How to identify Tiger's Eye

To correctly identify Tiger's Eye (Tiger's Eye (a variety of Quartz)), 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

   Golden-yellow, golden-brown, reddish-brown, sometimes with darker brown or black bands. Hawk's Eye (blue Tiger's Eye) is blue-gray to blue-green.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Silky to vitreous, especially on polished surfaces, with a distinct chatoyancy.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Fibrous, often visible as fine parallel lines or bands. Polished surfaces are smooth.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Massive, cryptocrystalline aggregates, typically forming veins or layers within host rock. Does not form macroscopic crystals.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None, as it is a variety of quartz.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Typically found in metamorphic rocks, particularly those rich in iron-bearing amphiboles. It forms in veins or layers within serpentinites or other altered ultramafic rocks.

Key Facts

Hardness

7 on the Mohs scale

Specific Gravity

2.64 - 2.71

Crystal System

Trigonal (as quartz)

Color

Golden-yellow, golden-brown, reddish-brown, blue-gray (Hawk's Eye)

Luster

Silky to vitreous

Transparency

Opaque to translucent

Fracture

Conchoidal to splintery (due to fibrous nature)

Cleavage

None

Composition

Silicon dioxide (SiO2) with inclusions of iron oxides and altered amphibole fibers.

Physical characteristics

• Crystal Habit: Massive, fibrous aggregates, pseudomorph after crocidolite.
• Cleavage Type: None (due to quartz composition).
• Fracture Type: Conchoidal to splintery, reflecting the fibrous structure.
• Tenacity: Brittle.
• Luster Type: Silky to vitreous, with strong chatoyancy.

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