glomerocryst

In geology, a glomerocryst is a textural feature found in igneous rocks. It refers to an aggregate of two or more crystals that are larger than the surrounding fine-grained matrix or groundmass. These aggregates are also known as glomeroporphyritic texture.1

While phenocrysts are individual large crystals in a porphyritic rock, glomerocrysts are clusters of these crystals. They can be composed of a single mineral type or multiple minerals. Sometimes, these large crystals or aggregates may not have formed from the host magma itself but could be fragments of pre-existing rock incorporated into the magma, in which case they are termed xenocrysts or xenoliths.1