Peanut Wood Jasper

Peanut Wood Jasper is a striking fossil material: silicified (petrified) ancient wood, dark brown to black, dotted with pale cream or white oval shapes that resemble scattered peanuts. It is essentially a form of agatized/jasperized wood, so chemically it is microcrystalline quartz (SiO2) replacing original woody tissue.

The famous white "peanuts" are not part of the wood's grain. They are filled boreholes made by ancient wood-boring clams (Teredo, the "shipworm") in driftwood that sank to the seafloor; the holes were later packed with pale sediment and silicified.

Most commercial peanut wood comes from the Kennedy Range area of Western Australia and dates to the Cretaceous period.

Peanut Wood Jasper began as logs and driftwood from Cretaceous forests that washed into the sea. While waterlogged and floating or resting on the seafloor, the wood was riddled with tunnels by Teredo shipworms (wood-boring bivalves).

The driftwood eventually sank into fine marine sediment. The shipworm boreholes filled with pale, light-colored radiolarian-rich mud, while the surrounding wood was buried in darker sediment. Over millions of years, silica-rich groundwater replaced both the wood and the borehole fillings cell by cell, fossilizing the whole mass into hard jasper/chalcedony.

The contrast between the dark silicified wood and the pale silicified borehole fillings produces the signature peanut-spot pattern.

Look for a hard, opaque dark brown-to-black stone studded with cream or white elongated oval "peanut" spots. It scratches glass (Mohs 6.5-7) and shows a white streak.

Key diagnostic: the white shapes are infilled borings, often elongate and randomly oriented, sometimes with visible wood grain in the dark matrix. This distinguishes it from spotted jaspers whose pattern is random staining.

Distinguish it from ordinary petrified wood (shows growth rings, lacks the peanut borings) and from leopard skin jasper (rounded orbs from volcanic origin, not fossil borings). Its fossil, sedimentary nature and locality are strong clues.

Peanut Wood Jasper is a popular lapidary and fossil-collector material, cut into cabochons, beads, slabs, spheres, and display pieces. Its bold contrast and unusual fossil story make it a favorite for distinctive jewelry and cabinet specimens.

It has no industrial use; value comes from its visual appeal and fossil interest. Toughness and a good polish make it suitable for pendants and rings.

Metaphysically it is associated with grounding, patience, and connection to deep time, claims that are spiritual rather than scientific. Well-patterned pieces with crisp peanut spots are the most prized.