Peanut Wood Jasper Identification Guide
How to identify peanut wood (fossil driftwood jasper) by its dark body with white teredo-bored spots, hardness, and look-alike comparisons.
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What Peanut Wood Jasper Looks Like
Peanut wood is silicified (petrified) fossil driftwood in which the original wood was bored by marine teredo "shipworms," and the boreholes later filled with pale silica. The result is a dark brown-to-black jasper/chalcedony body peppered with white, cream, or tan oval and elongated "peanut" spots (the filled borings). Luster is waxy to vitreous when polished, and it is opaque. Sometimes faint woody grain is still visible.
Quick visual cues
- Dark brown/black silica body with creamy white oval spots
- Spots are elongated, randomly oriented (the fossil borings)
- Waxy-to-glassy polish, opaque
- Occasional wood-grain texture in the matrix
Step-by-Step Field ID Checklist
- Inspect the white spots: they are elongated, tube-like, and irregular — clearly fossil borings, not crystals or banding.
- Confirm hardness: silicified wood is 6.5-7 Mohs; it scratches glass readily.
- Check fracture: conchoidal, with no cleavage.
- Look for wood structure: faint grain or ring traces may survive in the dark matrix.
- Heft and luster: dense, takes a high waxy polish.
- Streak: white.
Key Diagnostic Tests
- Mohs hardness: 6.5-7 (quartz-family silica).
- Streak: white.
- Cleavage/Fracture: none / conchoidal.
- Specific gravity: ~2.6.
- No acid reaction (distinguishes silica from any carbonate-filled fossils).
- Magnification: white fillings show fine chalcedonic/silica texture, not sugary calcite.
Common Look-Alikes and How to Tell Them Apart
- Dalmatian stone: rounded black dots in a pale body — the opposite color arrangement, and dots are mineral spots not borings.
- Other petrified wood: shows growth rings and cell structure but lacks the white teredo borehole spots.
- Flower/poppy jasper: spots are mineral rosettes or orbs, not elongated tubes.
- Black jasper with calcite veins: veins are linear and fizz in acid; peanut wood spots are oval and silica-filled (no fizz).
- Snowflake obsidian: glassy, softer (5-5.5), with spherulite spots rather than fossil borings.
The defining feature is the elongated white silica-filled teredo borings in a dark silicified-wood body, combined with hardness 7 and no acid fizz.
Where Peanut Wood Jasper Is Found
Peanut wood is best known from Western Australia (Kennedy Range / Gascoyne region), where Cretaceous driftwood sank, was bored by teredo clams, buried in seafloor mud, and replaced by silica. Similar bored-and-silicified wood occurs at a few other fossil-wood localities, but Australian material dominates the market.
Frequently asked questions
How can you tell if it's real peanut wood jasper?
Real peanut wood is silicified wood with elongated white silica-filled teredo borings in a dark body, hardness 6.5-7, conchoidal fracture, a white streak, and no acid reaction. Look for surviving wood grain in the matrix.
What does peanut wood jasper look like?
It is a dark brown-to-black polished silica stone scattered with creamy white oval and tube-shaped 'peanut' spots, which are fossil shipworm borings filled with light silica.
What are the white spots in peanut wood?
They are boreholes made by teredo marine clams (shipworms) in ancient driftwood, later filled with pale silica during fossilization.
Peanut wood vs dalmatian stone — how do I tell them apart?
Dalmatian stone is a pale rock with round black mineral spots, while peanut wood is a dark rock with elongated white silica-filled borings and visible wood grain.
Peanut Wood Jasper identified by the community
Recent Peanut Wood Jasper specimens identified with Rock Identifier.
