The Stone Bug is roughly the length of the last joint of the average thumb with a thorax much wider than its head and abdomen. The head hosts two thin antennae and a wide probiscis which it uses to consume a mixture of plant growth and mineral deposit which it dissolves itself by depositing a mixture of fluids from its enlarged thorax via its thin tube-like abdomen.
It is hotly contested whether the Stone Bug gets its name from how often many of its kind congregate on large rocks or from a popular belief that enough Stone Bug essence can melt through stone. The first is observable fact, the second is an old wives tale, but both are widely accepted. Either way the Stone Bug was considered a nuisance and a pest for centuries before its now common and popular use became apparent. The first experiments with Stone Bugs were likely for the creation of Sticky Stones, but the highly corrosive chemicals which combine perfectly when the bug is crushed quickly have made for useful cleaning purposes. Some Rugadh Sliabh have even begun to etch swords using extracted Stone Bug essence. Though not inherently dangerous as individuals the extraction of Stone Bug essence at large scale can be dangerous. Considering many young children will end up killing the creatures and get the mixture on their skin with little but a painful itch in consequence it was surprising to the first enterprising groups attempting to collect the substance en mass when the wooden tub they were storing the fluid in became a rapid health hazard, melting away and outputting fumes that burned the lungs and eyes. Modern Stone Bug collectors use large stone cases which have thin punctured lids that allow for controlled gas emissions and now can more affordably bottle the substance in glass vessels which were previously cost prohibitive. Titanium chainmail gloves double meshed with an underlying tough leather are used in the process of collecting, extracting and bottling Stone Bug Essence and they are crushed carefully with a large stone or marble pestle before the mixture is left to sit in its stone tank until the leftover Stone Bug parts dissolve and homogenize with the final concoction.