sedimentary

Hag Stone

Perforated Flint or Chert (SiO2)

Hardness: 6.5-7 (Mohs); Color: Tan, brown, gray, or cream; Luster: Dull to waxy; Structure: Microcrystalline; Feature: Naturally occurring through-hole.

Hardness: 6
Color: Tan, brown, gray, or cream
Luster: Dull to waxy

Identified May 26, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Tan, brown, gray, or cream; Luster: Dull to waxy; Structure: Microcrystalline; Feature: Naturally occurring through-hole.

Formation & geological history

Formed as flint/chert nodules in chalk or limestone during the Cretaceous period. The holes are created over millennia by wave action or acidic erosion, often where marine borers (like piddock clams) once lived.

Uses & applications

Primarily collected as a charm, decorative garden stone, or for use in jewelry and folk magic as a protective amulet.

Geological facts

Also known as Odin stones, witch stones, or adder stones, they were historically believed to protect against the 'evil eye' or to allow the bearer to see into invisible realms.

Field identification & locations

Identify by a hole that goes completely through the stone, formed naturally by water or fossils. Commonly found on beaches in the UK, Denmark, and the Great Lakes region.