Inspect the piece under a 10x or 20x jeweler's loupe. Pay close attention to high-relief areas, letters, and the junction where the suspension loop meets the medal body.
Use a 10x loupe and good lighting. Run your fingernail perpendicular across the line. If it catches going into the line, it’s a crack or scratch. If it catches on a raised ridge, it’s likely a die crack. medal crack
Rapid temperature changes cause metal to expand and contract. Leaving a medal in direct sunlight, near a radiator, or moving it from a cold environment to a warm, humid room can create microscopic stress fractures that eventually grow into visible medal cracks. Inspect the piece under a 10x or 20x jeweler's loupe
reported their medals literally cracking on the floor during celebrations. near a radiator