Interlocking crystals are a mineral structure characterized by crystals or grains tightly intergrown at random, producing a texture in which the mineral crystals and boundaries are nearly impossible to distinguish without magnification. When interlocking crystals of the same mineral appear, it is sometimes known as a granoblastic texture, a common texture in metamorphic rocks. Interlocking textures also occasionally appear in igneous rocks as the crystals grow simultaneously, preventing one or the other from developing perfect shapes. It sometimes appears as one large piece of mineral but is an accretion of many minerals of the same mineral species.