stone bubble

geology

Also known as: lithophysa

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July 14, 2026

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The term "stone bubble" in geology most accurately refers to a lithophysa. These are hollow, bubble-like or rose-like structures found within certain glassy rocks. They are characterized by concentric shells and often contain interspaces. Lithophysae can form from the chemical alteration of spherulites or from the expansion of gas bubbles as lava cools.1

Another related geological feature is an amygdule, which is a secondary mineral deposit found in rounded or almond-shaped cavities within igneous rock. These cavities, called vesicles, are formed by expanding gas bubbles or steam in lava. Amygdules are typically found near the tops of lava flows, and the minerals that fill them can form after the rock solidifies.2

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igneous rock
Small-scale structural features
Lithophysae, also known as stone bubbles, consist of concentric shells of finely crystalline alkali feldspar separated by empty spaces; thus, they resemble an onion or a newly blooming rose. Commonly associated with spherulites in glassy and partly crystalline volcanic rocks of salic composition, many lithophysae are about the size…
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Lithophysae, also known as stone bubbles, consist of concentric shells of finely crystalline alkali feldspar separated by empty spaces; thus, they resemble an onion or a newly blooming rose. Commonly associated with spherulites in glassy and partly crystalline volcanic rocks of salic composition, many lithophysae are about the size…
Read More

spherulite
Lithophysae are hollow, bubble-like or rose-like forms that occur within certain glassy rocks. They consist of concentric shells with hollow interspaces. Many are penetrated by parallel membranes, which are continuations of laminations in the enclosing rock. The shells may be lined with delicate crystals of…
Read More
Lithophysae are hollow, bubble-like or rose-like forms that occur within certain glassy rocks. They consist of concentric shells with hollow interspaces. Many are penetrated by parallel membranes, which are continuations of laminations in the enclosing rock. The shells may be lined with delicate crystals of…
Read More