fossil

Polished petrified wood

Silicified wood, primarily microcrystalline quartz (SiO₂) replacing cellular tissue

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, glassy to waxy luster, dense, and non-cleaving; this specimen shows polished brown, reddish, cream, and golden bands preserving wood-grain patterns. Specific gravity is commonly about 2.5–2.7.

Identified August 15, 2026More fossil →

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Physical properties

Formation & geological history

Buried wood was gradually permineralized and replaced by silica-rich groundwater, preserving cellular structure; individual specimens commonly date from tens to hundreds of millions of years old. It forms in volcanic ash beds, floodplains, and sedimentary basins.

Uses & applications

Used as ornamental stone, bookends, cabochons, carvings, countertops, and collectible display pieces. It is generally valued for pattern, polish, size, and locality rather than gem rarity.

Geological facts

The visible streaks and cellular textures are fossilized growth and vascular structures, not mineral banding alone. Agatized varieties may contain chalcedony, opal, or crystalline quartz.

Field identification & locations

Identify it by preserved wood grain, great density, hardness, and silica-like polish; a steel file usually scratches softer look-alikes but not quartz-rich material. Major sources include Arizona, Utah, Wyoming, Indonesia, Madagascar, and Argentina.