sedimentary

Banded Iron Formation (Jasper)

Banded Iron Formation (BIF), predominantly Microcrystalline Quartz (SiO2) and Hematite (Fe2O3)

Hardness: 6.5-7 (Mohs scale), Color: alternating bands of red jasper and gray/black iron oxides, Luster: dull to vitreous, Structure: microcrystalline/cryptocrystalline quartz, Cleavage: none (conchoidal fracture), Specific Gravity: 2.5-3.0

Hardness: 6

Identified July 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed billions of years ago in the Precambrian era (mostly 2.4 to 1.8 billion years ago) through the precipitation of iron and silica from ocean water as oxygen levels began to rise due to early photosynthesis.

Uses & applications

Primary source of iron ore globally; used in jewelry and lapidary arts as 'Jaspilite' and for ornamental carving.

Geological facts

These rocks provide 'snapshots' of the Earth's atmosphere's oxygenation, reflecting the rhythmic pulses of the Great Oxidation Event. Some specimens are among the oldest rocks on the planet.

Field identification & locations

Identified by distinct alternating color bands (often red/black or red/gray). Heavy for its size due to iron content. Commonly found in ancient shield areas like the Lake Superior region (USA), Western Australia, and Brazil.

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