Pseudomorphs are minerals that have replaced another, while keeping the crystal shape and habit of the original. This is a classic example of this rare replacement, showing hematite having completely replaced sharp and large magnetite crystals in a hot volcanic environment. These robust, three-dimensional crystals are really interesting to hold and look at, rich with small details. More recent examples from later years were not, perhaps, completely replaced; and in any case collecting is forbidden now. These came out in the late 1990s and this looks like one of the earlier style.