How to identify Red Jasper

To correctly identify Red Jasper (Chalcedony (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

   Opaque red, reddish-brown, brick-red, or sometimes mottled with other colors.

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

   Fine-grained, dense, and smooth when polished. Can feel slightly gritty on unpolished surfaces.

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

   Hydrothermal veins, volcanic rocks, sedimentary beds (especially banded iron formations), and as secondary infillings in various rock types. Often found in areas with past or present volcanic activity or significant hydrothermal alteration.

Key Facts

Hardness

6.5-7 on the Mohs scale

Specific Gravity

2.58-2.64 g/cm³

Crystal System

Trigonal (for quartz component)

Color

Red, reddish-brown, brick-red

Luster

Dull to vitreous, waxy on fracture

Transparency

Opaque

Fracture

Conchoidal

Cleavage

None

Composition

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

Physical characteristics

• Crystal Habit: Massive, cryptocrystalline aggregates, nodular, botryoidal, or as vein fillings.
• Cleavage Type: Absent
• Fracture Type: Conchoidal to splintery
• Tenacity: Brittle
• Luster Type: Dull to vitreous, waxy

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