Which texture describes igneous rock with a high glass content formed by very rapid cooling?

The texture that describes igneous rock with a high glass content formed by very rapid cooling is identified as glassy. This occurs when molten rock cools so quickly that crystals do not have time to form, resulting in a smooth, glass-like appearance. Rocks with this texture, such as obsidian, are typically formed by volcanic activity where lava is ejected and cools rapidly upon exposure to air or water.

In contrast, porphyritic texture refers to rocks that contain larger crystals embedded in a finer-grained matrix, indicating a two-stage cooling process rather than rapid cooling. Diorite is a coarse-grained igneous rock with a mix of minerals, typically formed from slower cooling processes, and basalt, while often fine-grained, typically consists of well-formed crystals and does not necessarily indicate high glass content. Therefore, glassy is the most precise term for describing this specific texture associated with very rapid cooling processes in igneous rocks.