I figured that the early 3-stage rock mon of my region should be about something more basic than the Bowen's Reaction Series. Although, I will keep that line, this would be a "version exclusive" featuring the rock cycle.
Igneous rocks are formed from magma or lava cooling down. Sedimentary rocks are formed from rocks fragments and minerals layering on top of each other, and metamorphic rocks are formed from pre-existing rocks being warped and chemically changed in structure due to heat and pressure. It is important to note that not all sedimentary rocks are formed from igneous rock fragments, and metamorphic rocks do not specify what kinds of rocks are being warped: a metamorphic rock can come from a different kind of metamorphic rock. These rock types are distinguished by how they are formed, and any rock can be melted again by some magma and turn into an igneous rock.
Igneone (Rock): Igneones can be seen coming out of the ground when there is any lava flowing on the surface. They can use their internal heat to warm up their bodies during combat, giving them an extra edge in their blows.
Sedislab (Rock/Ground): It is not uncommon to find multiple Sedislabs stacked on top of each other, especially while they are asleep. The rough sandy environments that Sedislabs live in help form the shape of their shell.
Metamolder (Rock/Ground): Metamolders often dwell underground, and despite their imposing stature, they are usually docile in their environments. When Metamolders get hot, usually by visiting lava hotspots, they can change the warped patterns on their body.