Vitrophyre

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.^[1] Vitrophyres can be alternatively described as rocks having vitrophyric texture.^[2] This texture results from the rapid quenching of a lava where phenocrysts had started to form prior to eruption.^[3]

Example of a rhyolitic vitrophyre; large phenocrysts are set in the black glassy matrix

See also

• Obsidian
• Poikilitic texture
• Tachylite