In this digital illustration project I wanted to show how different types of stones change over time. The illustration style is inspired by product design sketching which aims to communicate an idea or concept quickly to the viewer. My goal was to test if these strategies are also suited for the communication of scientific information. Moreover, it was incredibly enjoyable to test different ProCreate features to visualise the textures of different rocks and their parental rocks. 

There are three types of stones: igneous, dividing into volcanic (extrusive) or plutonic (intrusive) rocks, sedimentary or metamorphic rocks. In Geology, Metamorphosis is the change of texture, structure or composition of the rock. 

This first illustration shows Obsidian. This volcanic glass is rather unstable, so it crystallises over time and form snowflake Obsidian. Granite is a plutonic rock that changes into gneiss. It is one of the most resistent types of stones, but even these crystalline structures change when facing the immense mechanical energy of plate tectonics. The minerals of granite do appear unordered, but the pressure changes their direction, which creates the foliation you can see in the illustration foliation. The change from granite to gneiss is therefore not mineralogical, meaning there are no chemical changes. In contrary to granite and gneiss the metamorphosis of limestone to marble is a process of recrystallisation. For this process high temperatures and high pressure is needed.