The rock is probably a metamorphic rock.
If heat and pressure are involved in the formation of a rock and during the process, the rock does not become a liquid, the rock would be metamorphic rock which is formed under the above situations and became different from parent rocks.
In places where volcanism and crustal movement occurs, existing rock may be subjected to high temperatures and pressure. Under these circumstances, the properties of the rock will change, for example, the chemical composition and the textures, forming metamorphic rocks.
For example,granite will turn into gneiss under high pressure, and will turn into marble under extreme heat.
Hope it helps!