We have studied various microspherules (<0.5 mm across) that were found in Devonian sediments from Canada and China during our micropaleontological studies (e.g., conodont picking). These spherules are similar in appearance, but they are quite different in origin. A combined scanning electron microscope, energy dispersive X-ray, X-ray microdiffraction, and electron microprobe analysis enables us to determine their probable origins: phosphatic conodont pearls of biological origin; silicate glass microtektites of terrestrial meteorite-impact origin; and black, magnetic iron spherules of probable extraterrestrial origin. We also observed some contaminant spherules (glue spatters and steel slag) of artificial origins. Studies of natural spherules in sediments can provide important geological information that may be otherwise undetectable.