Stone Beetles

Found in the most mountainous and rocky regions of the world Stone beetles are small elementals which are native to the elemental plane of earth and over the years have come to inhabit the material plane as well. These small insects have an outer shell made of solid rock which forms their carapace. In some rare cases when they grow the get gemstone or crystalline carapaces instead. Growing to be around ten inches in length theses beetles start their life out as a grub hatching from an egg layer directly in rock. From there they grow and slowly carve out the interior of their rocky shell, once they are big enough they break the shell they’ve made from the stonework itself and begin to burrow and feed. This stage of their life lasts up to two years before they leave the rock and start a life on the surface.
At the surface they have few natural predators since breaking through their stony shell is a challenge for even the toughest of creatures, that was until an alchemical discovery was made. These beetles can be used to make potions that imitate the spell stone skin. By harvesting the rocky shell they make for themselves and using it in an alchemical nature you can harden your own skin. This discovery has caused trappers and hunters to start searching for them when they are traveling. The rarer gem varieties are more often harvested for decorative purposes rather than alchemical and will fetch a larger sum of coin.
The hunting of these creatures can be dangerous not due directly to the beetles but instead due to the fact that when the larva stage is burrowing in the rocks it often losses the stones and makes landslide much more common in the localized region. This has led to the development of traps designed to catch them to make the processes a bit safer. If you're able to catch one on the surface that is quite the feat, as they are sensitive to tremors and will quickly burrow in the rock for safety.