sedimentary

Hag Stone

Perforated Sedimentary Rock (typically Flint or Limestone)

AI-generated identification · may be incorrect

Hardness: 6-7 (if flint); Color: Dark grey, brown, or black with organic staining; Luster: Dull/Earthy; Crystal structure: Microcrystalline; Features a naturally occurring hole through the center due to erosion.

Hardness: 6-7 (if flint)
Color: Dark grey, brown, or black with organic staining
Luster: Dull/Earthy

Identified July 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through selective water erosion over thousands of years. Constant abrasion from running water, pebbles, or boring organisms (like piddock clams) creates a hole in softer parts of a sedimentary rock.

Uses & applications

Historically used as protective amulets, 'fairy stones,' or window charms. Today, they are popular among beachcombers, nature collectors, and practitioners of folk magic.

Geological facts

Also known as Odin stones, adder stones, or holy stones. According to European folklore, looking through the hole allows a person to see into the spirit realm or ward off the 'Evil Eye'.

Field identification & locations

Found along riverbeds and coastlines. Identify by looking for a hole that has been clearly worn smooth by natural elements rather than drilled by tools. Common in the UK and coastal US.