Hadrosaur Eggshell Fragment or Dinosaur Egg Geode
aff. Hypselosaurus or cf. Elongatoolithidae based on texture • Body fossil (Reproductive) / Perichondral replacement
Geological Period
Late Cretaceous (approx. Campanian to Maastrichtian)
Estimated Age
72 to 66 million years ago
Preservation Type
Mineralization with silica/calcite replacement and sediment infilling
Condition Assessment
Fair to Poor; significant weathering of the surface texture and lack of distinct shell pattern definition
Taxonomic Classification
Phylum: Chordata, Class: Reptilia, Order: Ornithischia, Family: Hadrosauridae (likely)
Morphological Description
Rounded, globular mass with a pitted, porous surface texture characteristic of dinosaurian eggshells. Shows secondary mineralization and possible internal geodization.
Rock Matrix
Sandy siltstone or fine-grained mudstone, typically associated with terrestrial floodplain deposits
Formation & Location
Commonly found in the Hell Creek Formation (USA), Djadochta Formation (Mongolia), or the Nanxiong Formation (China)
Size & Dimensions
Approximately 3-5 cm in diameter; appears to be a small nodular fragment or a small individual egg
Value & Rarity
Estimated Market Value
$40 - $120 USD
Auction Estimate
$50 - $150 USD
Rarity Assessment
Uncommon as a complete specimen, but fragments from these regions are relatively common in the fossil trade
Scientific Significance
Provides evidence of nesting sites and reproductive strategies of Late Cretaceous dinosaurs in terrestrial environments
Preparation Recommendations
Mechanical cleaning using air-abrasion with soft media; keep in a low-humidity, stable environment to prevent matrix expansion
Notable Features
The specimen exhibits a heavy reddish iron-oxide staining and a suggestive sub-spherical shape that indicates it may be a partial egg cast