What is another word for volcanic glass?
Pronunciation: [vɒlkˈanɪk ɡlˈas] (IPA) 
Volcanic glass, also known as obsidian, is a naturally occurring substance formed from molten lava that has rapidly cooled without crystallizing. There are several synonyms for volcanic glass, including natural glass, lava glass, and tachylyte. Tuff is another related term, which refers to a rock made of volcanic ash and other materials that have been compacted and cemented together. Although volcanic glass may look like a rock, it is actually an amorphous solid, which means it lacks a crystalline structure. This unique characteristic makes it an important material for tools, weapons, and decorative objects in various cultures throughout history.
