How to identify Red Jasper

To correctly identify Red Jasper (Jasper (variety of Chalcedony, SiO2)), 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, brownish-red, or deep red, often uniform but can exhibit subtle banding or patterns.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Dull to vitreous, sometimes waxy on fractured surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth to slightly granular, opaque.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Massive, cryptocrystalline aggregates; individual crystals are microscopic and not visible to the naked eye.

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 association with volcanic rocks, hydrothermal alteration zones, sedimentary deposits (especially those rich in iron), and as a replacement mineral in various host rocks. Often occurs in veins, nodules, and as bedded deposits.

Key Facts

Hardness

6.5-7 on the Mohs scale

Specific Gravity

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

Crystal System

Trigonal (cryptocrystalline aggregates)

Color

Red, brick red, brownish-red, due to hematite inclusions

Luster

Dull, waxy, or vitreous

Transparency

Opaque

Fracture

Conchoidal to splintery

Cleavage

None

Composition

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

Physical characteristics

• Crystal Habit: Massive, cryptocrystalline, granular aggregates; individual crystals are microscopic.
• Cleavage Type: None
• Fracture Type: Conchoidal to splintery, uneven
• Tenacity: Brittle
• Luster Type: Dull to vitreous, sometimes waxy

Explore Red Jasper