How to identify Tiger's Eye

To correctly identify Tiger's Eye (Tiger's Eye (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 blue (Hawk's Eye) or red (heated) variations. The colors are typically banded or streaky.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Silky to vitreous, especially on polished surfaces, due to the fibrous structure.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Fine-grained, fibrous appearance internally, often smooth and polished externally for gemstones.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

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

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None, as it is a cryptocrystalline variety of quartz.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Typically found in metamorphosed igneous or sedimentary rocks where crocidolite has been altered. Often occurs in banded iron formations or serpentinites.

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 (due to limonite inclusions)

Luster

Silky (due to fibrous structure) to vitreous

Transparency

Opaque to translucent

Fracture

Conchoidal to splintery

Cleavage

None

Composition

Silicon dioxide (SiO2) with fibrous inclusions of altered crocidolite and iron oxides.

Physical characteristics

• Crystal Habit: Massive, fibrous aggregates, pseudomorphous after crocidolite.
• Cleavage Type: None (due to cryptocrystalline nature).
• Fracture Type: Conchoidal to splintery, reflecting the fibrous internal structure.
• Tenacity: Brittle.
• Luster Type: Silky to vitreous.

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