Purpose: To clarify the origin of a metallic intraocular foreign body (IOFB) due to a firecracker injury and to show the utility of X-ray diffraction analysis in the identification process. Methods: Interventional case report using X-ray diffraction technique. Results: We report a mechanism of firecracker ocular injury not previously described in the published literature. It involved penetration into the eye by a ground particle of calamine (originated from the area of detonation) and not, as...