igneous
Iron-stained quartz-rich breccia (likely weathered vein rock)
Quartz-rich hydrothermal breccia with limonite/goethite; possibly iron-bearing jasper or silicified volcanic rock
AI-generated identification · may be incorrectBrown, ochre, gray, and cream angular fragments cemented by iron oxides and silica; dull to locally glassy/waxy luster, irregular fracture, no obvious cleavage. Quartz hardness ~7 Mohs; iron-oxide coatings are softer and may streak yellow-brown to reddish-brown.…
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Physical properties
Brown, ochre, gray, and cream angular fragments cemented by iron oxides and silica; dull to locally glassy/waxy luster, irregular fracture, no obvious cleavage. Quartz hardness ~7 Mohs; iron-oxide coatings are softer and may streak yellow-brown to reddish-brown. The cavity and angular texture are consistent with brecciation rather than a single crystal.
Formation & geological history
Likely formed when silica-rich hydrothermal fluids fractured and cemented older rock, followed by oxidation of iron-bearing minerals near the surface. Exact age cannot be determined visually; this material is geologically plausible in the Pacific Northwest, including the Columbia River region, where volcanic and hydrothermal rocks are common.
Uses & applications
Mostly a collecting or lapidary specimen; attractive pieces may be polished. Iron-rich breccia has limited industrial value compared with ordinary aggregate or iron ore.
Geological facts
The metallic-looking patches are probably goethite/limonite rather than native metal. A magnet test may show weak attraction if magnetite is present; a streak test and fresh-break inspection would help distinguish jasper, quartz vein, and altered volcanic rock.
Field identification & locations
Look for angular clasts, silica-rich hard areas, rusty staining, and a yellow-brown streak. Common regional alternatives include weathered basalt, jasper, and quartz-vein material; acid testing, hardness testing, and a close fresh surface are needed for a firmer ID.
