Petrified Wood (Polished Agatized/Chertified Wood Fragment)
Indeterminate woody plant taxon (cf. Araucarioxylon sp. or similar permineralized gymnosperm/angiosperm wood) • Body fossil (permineralized/petrified plant tissue, paleobotanical)
Geological Period
Late Triassic to Eocene (commonly Triassic Chinle Formation or Eocene Green River/Clarno Formation)
Estimated Age
50 to 225 million years old
Preservation Type
Permineralization and silification/agatization (cellular space filled and replaced by silica minerals such as chalcedony, jasper, and quartz)
Condition Assessment
Good to Very Good (stable polished face with typical natural internal micro-fractures)
Taxonomic Classification
Kingdom: Plantae, Division: Tracheophyta, Class: Spermatopsida (Gymnospermae or Angiospermae indeterminate)
Morphological Description
Roughly rectangular block displaying a polished face with microcrystalline silica replacement. Shows distinct color zoning ranging from deep brown and tan to bluish-grey cryptocrystalline chalcedony/agate centers, along with fine linear fractures and remnants of cellular grain structure.
Rock Matrix
Self-contained permineralized material with minor chalcedonic matrix and secondary iron oxide mineralization giving rich yellow-brown tones
Formation & Location
Commonly sourced from Western North America (e.g., Chinle Formation in Arizona/Utah, or Eocene formations in Oregon, Wyoming, or Madagascar)
Size & Dimensions
Approximately 5 cm to 8 cm in length, representing a small cut/polished slab fragment
Value & Rarity
Estimated Market Value
$10 - $25 USD
Auction Estimate
$15 - $30 USD (typically sold in bulk lots or small decorative polished specimen sales)
Rarity Assessment
Common (petrified wood is widely distributed globally and frequently harvested for lapidary use)
Scientific Significance
Demonstrates silica-rich hydrothermal/groundwater paleoenvironments and the process of permineralization preserving ancient terrestrial forest flora
Preparation Recommendations
No further mechanical preparation required. Keep clean with a soft dry cloth; avoid harsh acids to protect the polished surface.
Notable Features
Distinct polished surface showcasing rich jasperoid brown-orange coloration contrasting with a translucent bluish agate core pocket and natural network fractures.