He also discovered the Neumann lines, now named after him, thin straight scratches that appear when some iron meteorites are cut open and the exposed surface polished.
Siya rin natuklasan ang Neumann linya, ngayon may pangalan na matapos sa kanya, manipis tuwid scratches na lalabas kapag ilang bakal meteorites ay bukas na cut at ang exposed ibabaw makintab.