Agatized or Petrified Wood Fragment in Matrix
Indeterminate Gymnosperm (cf. Araucarioxylon or Woodworthia species) • Body fossil / Petrified plant matter (Perpetuated through permineralization)
Geological Period
Likely Triassic to Lower Cretaceous
Estimated Age
Approx. 100 to 220 million years
Preservation Type
Permineralization (Silicification). Organic cellular spaces have been replaced and filled by silica/quartz minerals, retaining the original structure.
Condition Assessment
Fair. The specimen is a fragmented piece rather than a complete log section, showing significant weathering and partial concealment by the remaining matrix.
Taxonomic Classification
Kingdom: Plantae; Phylum: Tracheophyta; Class: Pinopsida (conifer-like)
Morphological Description
The specimen exhibits visible vertical grain structures and longitudinal tracheid patterns typical of woody tissue. The surface shows fibrous splintering where the wood was broken before Or during fossilization, and some areas show concentric growth ring fragments.
Rock Matrix
Iron-rich mudstone/siltstone conglomerate or sandstone with hematite staining, providing a reddish-brown earthy appearance.
Formation & Location
Commonly found in the Chinle Formation (Southwestern USA) or similar Mesozoic continental deposits such as the Hell Creek or Morrison Formations.
Size & Dimensions
Approximately 5-8 cm in length (hand-sized fragment), which is a common small-to-medium size for found weathering debris.
Value & Rarity
Estimated Market Value
US $15 - $35
Auction Estimate
US $10 - $25 (Best suited for bulk natural history lots or education sets)
Rarity Assessment
Common. Petrified wood is globally abundant, though high-quality 'opalized' or 'agatized' specimens with bright colors are more sought after.
Scientific Significance
Provides evidence of paleo-botanical diversity and ancient forest ecosystems; helps reconstruct regional paleoclimates and the transition of terrestrial vegetation.
Preparation Recommendations
Mechanical cleaning with a soft brush and water to remove loose dust. A light application of paraloid B-72 could consolidate crumbly matrix areas, though many collectors prefer it in its raw state.
Notable Features
Features a distinct contrast between the dark, silicated wood fibers and the reddish sedimentary matrix, indicating high mineral content in the groundwater during the replacement process.