sedimentary

Flint

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on Mohs scale, typically brown to dark gray or black color, waxy to vitreous luster, cryptocrystalline structure, conchoidal fracture with no cleavage, and a specific gravity of 2.60 to 2.65.

Identified October 19, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms by the replacement of calcium carbonate in chalk or limestone by silica-rich solutions during diagenesis in marine environments.

Uses & applications

Historically used for making stone tools, weapons, and fire-starting flint-locks; modern uses include aggregate, ceramics, and lapidary specimens.

Geological facts

Flint and chert are chemically identical, though 'flint' typically refers to varieties found in chalk formations that were heavily utilized by prehistoric humans.

Field identification & locations

Identified by its distinctive conchoidal fracture and sharp edges, commonly found embedded in chalk deposits worldwide, and easily recognized by striking steel to create sparks.