+**Volcanic glass** is an amorphous [igneous rock](/wiki/igneous_rock) formed when molten [lava](/wiki/lava) cools too rapidly for crystals to grow. This natural glass, often dark and shiny, breaks with a conchoidal fracture, creating very sharp edges.
+## See also
+- [Obsidian](/wiki/obsidian)
+- [Pumice](/wiki/pumice)
+- [Volcano](/wiki/volcano)
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