sedimentary

Fossil / Permineralized Bone

Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)

AI-generated identification · may be incorrect

Hardness: 5 (variable based on mineral replacement); Color: Dark brown to black (likely iron or manganese staining); Luster: Dull to sub-metallic; Structure: Porous micro-structure of original bone; Specific gravity: Varies by mineral content.

Hardness: 5 (variable based on mineral replacement)
Color: Dark brown to black (likely iron or manganese staining)
Luster: Dull to sub-metallic

Identified April 6, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed via permineralization where minerals like silica or calcite fill the pores of bone buried in sediment. This specimen originates from the Late Cretaceous period (approx. 66-68 million years ago).

Uses & applications

Predominantly used for scientific research, museum exhibitions, and high-end private collections.

Geological facts

This appears to be a Tyrannosaurus rex skull. The most complete T. rex ever found, 'Sue', is housed at the Field Museum. T. rex fossils are found exclusively in the Hell Creek, Lance, and Ferris formations of North America.

Field identification & locations

Identify in the field by looking for 'bone texture' (the spongy appearance of cancellous bone) in sedimentary layers. Usually found in floodplains or river channel sandstone. Professional excavation is required for preservation.