Vitrophyre

{{Short description|Glassy volcanic rock}}

File:Rhyolitic vitrophyre.jpg vitrophyre; large phenocrysts are set in the black glassy matrix]]

A vitrophyre is a porphyritic volcanic rock in which phenocrysts are embedded in a glassy matrix. Vitrophyres are contrasted from typical porphyritic rocks in that the latter has both crystalline phenocrysts (larger grains) and a crystalline matrix (smaller grains), whereas the former has a distinctly glassy matrix.{{cite book|title=Igneous and Metamorphic Petrology|page=27|last=Best|first=Myron G.|year=2002 |publisher=Blackwell Publishing|isbn= 9781405105880}}

Vitrophyres can be alternatively described as rocks having vitrophyric texture.{{cite book|title=Principles of Igneous and Metamorphic Petrology|page=40|last=Winter|first=John D.|year=2014 |publisher=Pearson|isbn=9781292021539}} This texture results from the rapid quenching of a lava where phenocrysts had started to form prior to eruption.{{cite book|title=Principles of Igneous and Metamorphic Petrology|last1=Philpotts|first1=Anthony|last2=Ague|first2=Jay|year=2009 |publisher=Cambridge University Press|page=198|isbn=9780521880060}}