Discussions taking place within this forum are intended for the purpose of assisting you in discussing options with your vet. Any other use of advice given here is done so at your risk, is solely your responsibility and not that of this forum or its owner. Before posting it is your responsibility you abide by this Statement
These are the dried remains of a calcium, which is the normal way of the body to excrete excess calcium.
A one off or an occasional pee is nothing to worry about unless you see a lot of it on a near daily basis. In that case, you may want review your diet and see your vet if you notice signs of problems in the urinary tract (red pees that may or may not contain blood and squeaking when peeing). Long Term Balanced General And Special Needs Guinea Pig Diets