fossil

Petrified Bone Pebble

Silicified Fossilized Bone

Hardness: 6.5-7 (Mohs), Color: Black and cream/tan with a network of fine web-like patterns, Luster: Dull to waxy, Structure: Reticulated cellular structure visible on the surface.

Hardness: 6

Identified July 3, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs), Color: Black and cream/tan with a network of fine web-like patterns, Luster: Dull to waxy, Structure: Reticulated cellular structure visible on the surface.

Formation & geological history

Formed through permineralization where minerals (usually silica) replace the organic cellular structure of bone over millions of years. This piece appears to be a stream-tumbled waterworn fragment.

Uses & applications

Scientific study, personal collection, jewelry (wire wrapping), or decorative lapidary work.

Geological facts

The 'brain-like' or net-like pattern on the surface is actually the fossilized remains of the trabecular or cancellous (spongy) bone structure. This allows paleontologists to distinguish bone from ordinary rocks.

Field identification & locations

Identify in the field by looking for 'pores' or honeycomb patterns that differ from the surrounding matrix. High-quality pieces are often found in the Morrison Formation in the USA.