Kruchy and other 85,000 icons from Icons8 icon pack follow the visual guidelines of the operating systems: Windows, iOS, Android KitKat, and Material. PNG format is free up to 100x100 px. Icons are availble for download in PNG and vector (SVG, PDF, EPS, and more).
This is an image of a wine glass. The wine glass has a crack from the top rim going down into the middle. This is exactly like the image you would see on many boxes to indicate "fragile" or "breakable" items within.