Prophecy Stone is a type of hematite and limonite pseudomorph after marcasite and pyrite. A pseudomorph is kind of like a "fossil" of another stone. A crystal (in this case, marcasite &/or pyrite) will form and then more rock will form around that. The crystal then dissolves or melts and reforms as a different crystal (in this case hematite &/or limonite). To be "prophecy stones," the pseudomorphs must originate from the Egyptian portion of the Libyan Desert. These specimens are from Farafra, Egypt.
Prophecy Stones were supposedly used in Ancient Egyptian religion, but I haven't been able to find any reliable sources on that. What I can tell you is that in the modern era, these are very powerful stones with connections to psychic healing and metaphysical awareness.
You are not guaranteed a specific specimen from the photos.