sedimentary

Chert (Flint/Novaculite)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 Mohs; Color: White to light gray; Luster: Waxy to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 6
Color: White to light gray
Luster: Waxy to dull

Identified June 21, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 Mohs; Color: White to light gray; Luster: Waxy to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed by the accumulation of siliceous remains of marine organisms or through chemical precipitation in sedimentary environments. Common in Paleozoic and Mesozoic rock layers.

Uses & applications

Historical use for stone tools and weapons (flint knapping); currently used in road construction aggregate, as sharpening stones (novaculite), and in glass manufacturing.

Geological facts

Chert is so hard it can scratch steel and was one of the primary materials used by prehistoric humans to start fires and make arrowheads due to its sharp, glass-like fracture patterns.

Field identification & locations

Identify in the field by its smooth, waxy surface and conchoidal (curved/shell-like) fractures. Found globally in limestone formations and as nodules in stream beds.