How to identify Tiger Iron

To correctly identify Tiger Iron (Tiger Iron (a banded variety of Jasper, Hematite, and Tiger's Eye)), 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

   Distinctive alternating bands of metallic gray (hematite), deep red (jasper), and golden-brown to yellow (tiger's eye).

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Bands of hematite exhibit a metallic luster; jasper is dull to vitreous; tiger's eye displays a silky, chatoyant luster.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Fine-grained to microcrystalline, with a smooth feel when polished. The tiger's eye component may show a fibrous texture.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Not applicable as a composite rock. Individual mineral components are cryptocrystalline (jasper, tiger's eye) or massive (hematite).

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None observed in the composite rock. Hematite has no cleavage, jasper and tiger's eye (quartz) have no cleavage.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Formed in ancient marine basins as chemical sediments, subsequently metamorphosed. Found in regions with extensive Precambrian banded iron formations.

Key Facts

Hardness

6.5-7 on the Mohs scale (due to quartz/jasper components), but can vary slightly with hematite content.

Specific Gravity

Approximately 3.3-4.0, varying with the proportion of hematite (higher density) to quartz (lower density).

Crystal System

Not applicable as a composite rock. Quartz is trigonal, Hematite is trigonal.

Color

Alternating bands of red (jasper), metallic gray (hematite), and golden-brown/yellow (tiger's eye).

Luster

Metallic (hematite), dull to vitreous (jasper), silky/chatoyant (tiger's eye).

Transparency

Opaque.

Fracture

Conchoidal to uneven (due to quartz/jasper components).

Cleavage

None.

Composition

A composite of microcrystalline quartz (jasper), fibrous quartz pseudomorphs after crocidolite (tiger's eye), and iron oxide (hematite).

Physical characteristics

• Crystal Habit: Massive, banded.
• Cleavage Type: None.
• Fracture Type: Conchoidal to uneven.
• Tenacity: Brittle.
• Luster Type: Metallic, dull, vitreous, silky.

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