Crushed Gemstone is the useless remains of a semi-precious gem that was cut with a chisel unsuccessfully. The player receives 75% less Craftingexperience for their effort. As the player's Crafting level increases, the chance of failing to cut semi-precious gems decreases.[Verify]
Crushed gemstone is perhaps[Verify] the only item received as the result of failure during production that also yields experience. Burnt or improperly prepared food and drinks provide no such exp.
Big netFishing has a chance of catching generally unwanted items like leather gloves and boots, but that is a gathering skill and none of those items are actually useless.