How to identify Red Jasper

To correctly identify Red Jasper (Jasper (a variety of Chalcedony, microcrystalline 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

   Typically brick red, brownish-red, or deep red. The color is generally uniform but can sometimes show subtle banding or mottling.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Dull to vitreous, often 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 veins, sedimentary chert beds, and as nodules or concretions in various sedimentary formations.

Key Facts

Hardness

7 on the Mohs scale

Specific Gravity

2.58 - 2.64

Crystal System

Trigonal (cryptocrystalline aggregates)

Color

Red, reddish-brown, brick red

Luster

Dull to vitreous, waxy

Transparency

Opaque

Fracture

Conchoidal

Cleavage

None

Composition

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

Physical characteristics

• Crystal Habit: Massive, cryptocrystalline aggregates, often forming nodules, veins, or beds.
• Cleavage Type: None
• Fracture Type: Conchoidal, producing sharp, curved surfaces.
• Tenacity: Brittle to tough.
• Luster Type: Dull to vitreous, sometimes waxy on fresh fracture surfaces.

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