igneous
Vesicular Basalt or Hag Stone
Basalt (with vesicles) or bored Sedimentary Rock
Hardness: 5-7 (Mohs scale), Color: tan to grey-brown, Luster: dull/earthy, Crystal structure: aphanitic (fine-grained), includes numerous small pits or vesicles.
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Physical properties
Hardness: 5-7 (Mohs scale), Color: tan to grey-brown, Luster: dull/earthy, Crystal structure: aphanitic (fine-grained), includes numerous small pits or vesicles.
Formation & geological history
Formed from the cooling of lava (if igneous) or through the action of boring organisms or wave erosion (if sedimentary). Found in volcanic regions or coastal environments where water action creates smooth, pitted surfaces.
Uses & applications
Construction aggregate, decorative landscaping, and occasionally as 'Hag Stones' for folklore or charms.
Geological facts
Stones with natural holes were once believed to ward off evil spirits and bad luck. If igneous, the holes are called vesicles and were formed by trapped gas bubbles in lava.
Field identification & locations
Identify by its pitted surface and relatively heavy weight for its size. Common on beaches and in fields near volcanic activity. Highly durable and resistant to weathering.
