miarole

geology

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June 30, 2026

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Miarolitic refers to a type of igneous rock characterized by irregular cavities. Within these cavities, well-formed crystals project outwards. This texture is often found in granites and is indicative of local concentrations of gases during the late stages of the rock's formation. These cavities, known as miaroles or miarolitic cavities, can be lined with crystals. The term originates from Italian dialect, meaning granite with small cavities.12

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igneous rock
Small-scale structural features
…these small interior bodies, called miaroles, contain centrally disposed crystal-lined cavities that are known as druses or miarolitic cavities. An internal zonal disposition of minerals also is common, and the most characteristic sequence is alkali feldspar with graphically intergrown quartz, alkali feldspar, and a central filling of quartz. Miarolitic structure…
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…these small interior bodies, called miaroles, contain centrally disposed crystal-lined cavities that are known as druses or miarolitic cavities. An internal zonal disposition of minerals also is common, and the most characteristic sequence is alkali feldspar with graphically intergrown quartz, alkali feldspar, and a central filling of quartz. Miarolitic structure…
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