How to identify Peanut Wood Jasper

To correctly identify Peanut Wood Jasper (Silicified fossil wood (Jasper variety)), 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

   Dominantly dark brown to black matrix with contrasting white, cream, or tan 'peanut-shaped' inclusions. Other colors like reddish-brown or grey may also be present in the matrix.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Dull to waxy or vitreous when polished.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Fine-grained, dense, and smooth when polished. The 'peanut' inclusions may have a slightly different texture or sheen.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cryptocrystalline, meaning individual crystals are too small to be seen without high magnification. It retains the macroscopic structure of the original wood.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None, as it is a cryptocrystalline aggregate of quartz.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Marine sedimentary environments where driftwood was infested by marine borers and subsequently buried and silicified. Often found in ancient marine deposits.

Key Facts

Hardness

6.5-7 on the Mohs scale

Specific Gravity

2.58-2.64

Crystal System

Trigonal (as cryptocrystalline quartz)

Color

Dark brown to black matrix with white, cream, or tan 'peanut' inclusions

Luster

Dull to waxy, vitreous when polished

Transparency

Opaque

Fracture

Conchoidal to splintery

Cleavage

None

Composition

Silicon dioxide (SiO2) with various impurities

Physical characteristics

• Crystal Habit: Massive, cryptocrystalline aggregate, pseudomorph after wood
• Cleavage Type: None
• Fracture Type: Conchoidal to splintery
• Tenacity: Brittle
• Luster Type: Dull to waxy

Explore Peanut Wood Jasper