sedimentary

Hag Stone

Perforated Sedimentary Rock (typically Flint, Chert, or Limestone)

Hardness varies depending on the host rock (generally 4-7 on the Mohs scale for chert/flint-based stones); color ranges from light gray to tan and brown; dull to vitreous luster; cryptocrystalline structure; no true cleavage; specific gravity around 2.6-2.7.

Identified August 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through natural weathering processes, where softer inclusions, fossils, or minerals within a sedimentary rock (such as limestone or chalk) erode away faster than the surrounding matrix, leaving a natural hole through the center.

Uses & applications

Historically used as an amulet or talisman for protection against evil spirits, nightmares, and magic; often collected as a curiosity or good luck charm.

Geological facts

Also known as adder stones, hole stones, or witch stones. Folklore in various European cultures suggests looking through the hole allows the viewer to see fairies, spirits, or hidden truths.

Field identification & locations

Found in stream beds, river gravels, and along coastlines where water action accelerates the erosion of soft spots in rocks. Easily identified by the naturally formed hole passing completely through the stone.

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