A baffling intrusion.
The brown obsidian artifact depicted in the picture, likely from the Early to Middle Pleistocene, was collected by the author in 1973 in a zone approximately midway between Lake Afrera and the village of Sardò in Dankalia (Ethiopia). See "Two artifacts from unexplored zones in-between Australopithecus afarensis (Lucy) and Homo buia"; it has been certified as authentic by some friendly paleontologists from the Italian Museum of Florence. Some time ago, taking some pictures of the same, I noticed on one of its sides something not in harmony with its composition and, enlarging the picture, what seemingly is a small intrusion, less than 2mm, was clearly visible in the middle of the artifact. Nothing really strange, were it not that - as clearly visible in the picture - it is quite baffling as it appears like a small metallic object which can be obtained only with a micro-mechanical procedure. Hence here I publish two pictures of the artifact, front and rear sides, and an enlargement of the portion containing the baffling object. The rest is left to your perception and imagination.

Left: obsidian artifact. Center: obsidian artifact, opposite side. Right: the baffling intrusion in the artifact.
Click images to enlarge