How to identify Red Jasper

To correctly identify Red Jasper (SiO2 (microcrystalline quartz with hematite inclusions)), 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 brick red, deep red, reddish-brown, or scarlet. The color is generally uniform but can exhibit patterns or banding.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Dull to vitreous, often waxy when polished.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, dense, and fine-grained. Non-granular.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Massive, cryptocrystalline aggregates. Individual crystals are microscopic.

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 deposits, particularly associated with banded iron formations (BIFs), volcanic rocks (as infillings or altered tuffs), hydrothermal veins, and as nodules or concretions in limestones and shales.

Key Facts

Hardness

6.5-7 on the Mohs scale

Specific Gravity

2.58-2.91 g/cm³ (typically around 2.65-2.70)

Crystal System

Trigonal (due to its quartz composition, though cryptocrystalline)

Color

Red, brick red, reddish-brown, scarlet

Luster

Dull, waxy, or vitreous

Transparency

Opaque

Fracture

Conchoidal to sub-conchoidal

Cleavage

None

Composition

Silicon dioxide (SiO2) with iron oxide (hematite, Fe2O3) inclusions

Physical characteristics

• Crystal Habit: Massive, cryptocrystalline aggregates, often nodular or as infillings.
• Cleavage Type: Absent
• Fracture Type: Conchoidal to sub-conchoidal, producing sharp edges.
• Tenacity: Brittle
• Luster Type: Dull to waxy or vitreous

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