sedimentary

Chert (with Quartz Vein)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Grayish-green with white veins; Luster: Waxy to vitreous; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Grayish-green with white veins
Luster: Waxy to vitreous

Identified June 6, 2026More sedimentary →

Explore Chert (with Quartz Vein) in the encyclopedia →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich organic remains or chemical precipitation in marine environments. The white veins are later quartz infills in cracks caused by tectonic stress.

Uses & applications

Historically used for stone tools and flintknapping. Currently used as decorative river stones, in landscaping, or as tumbled collector and lapidary pieces.

Geological facts

Chert is one of the most durable sedimentary rocks. When it contains a cross or 'X' pattern of veins, it is sometimes referred to as a 'lucky stone' or 'cross stone' by beachcombers.

Field identification & locations

Identify by its waxy texture, smooth water-worn surface, and ability to scratch glass. Commonly found on beaches, riverbeds, and in limestone outcrops.