sedimentary/metamorphic

Hag Stone (Holed Quartzite Pebble)

Quartzite (SiO2 based) with natural vug or erosion hole

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale), Color: tan, grey, and buff with sandy textures, Luster: dull to earthy, Structure: microcrystalline quartz grains, Cleavage: none, Specific Gravity: approx 2.6

Identified June 25, 2026More sedimentary/metamorphic →

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Physical properties

Hardness: 7 (Mohs scale), Color: tan, grey, and buff with sandy textures, Luster: dull to earthy, Structure: microcrystalline quartz grains, Cleavage: none, Specific Gravity: approx 2.6

Formation & geological history

Formed initially from sandstone through metamorphism, and later tumbled in high-energy aquatic environments (rivers or shorelines). The hole is often created by boring organisms like piddock clams or by the preferential weathering of a softer mineral inclusion like calcite.

Uses & applications

Historically used as protective amulets in folklore to ward off evil spirits or 'the evil eye'. Today used for decorative garden stones, jewelry, and by mineral collectors interested in curious geological shapes.

Geological facts

In European folklore, looking through the hole of a hag stone was believed to reveal the 'invisible world' of fairies or spirits. They are also known as adder stones, witch stones, or holy stones.

Field identification & locations

Identify by looking for a naturally occurring hole that penetrates the entire stone or a deep natural cavity. Commonly found on beaches or in riverbeds where water erosion is constant.