How to identify Red Jasper with Hematite

To correctly identify Red Jasper with Hematite (SiO2 (Jasper) with Fe2O3 (Hematite)), 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 opaque red, reddish-brown, or brick-red, often with darker red or metallic gray streaks or patches where hematite concentration is higher. The red color is due to hematite (Fe2O3).

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Dull to vitreous (glassy) on fractured surfaces; waxy to sub-vitreous when polished.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, dense, and fine-grained. Can feel slightly gritty if the hematite is more granular or if it's a less pure form.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Massive, cryptocrystalline (microscopic crystals). Does not exhibit macroscopic crystal forms.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None. Exhibits conchoidal fracture.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Found in sedimentary environments, often associated with ancient seafloors where iron-rich sediments and silica precipitated. Also occurs in hydrothermal veins, volcanic rocks, and as secondary mineralization in weathered iron-rich deposits. Commonly found in Banded Iron Formations (BIFs).

Key Facts

Hardness

6.5 - 7 on the Mohs scale (due to quartz/jasper component).

Specific Gravity

2.58 - 2.91 (varies with hematite content; pure jasper is ~2.65, hematite is 5.26).

Crystal System

Trigonal (for quartz/jasper component); Hexagonal (for hematite component).

Color

Red, reddish-brown, brick-red, due to hematite inclusions.

Luster

Dull, waxy, or sub-vitreous.

Transparency

Opaque.

Fracture

Conchoidal to splintery.

Cleavage

None.

Composition

Silicon dioxide (SiO2) with iron oxide (Fe2O3) inclusions.

Physical characteristics

• Crystal Habit: Massive, cryptocrystalline aggregates.
• Cleavage Type: None.
• Fracture Type: Conchoidal to splintery.
• Tenacity: Brittle.
• Luster Type: Dull, waxy, sub-vitreous.

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