Yuh this actually sometimes becomes an issue here. LoL that the teenage clerks in the local stores often have no idea what the different paint colors on the ends of the rods mean. Red green yellow and blue I have rods with all 4. 80% of the time it all means nothing anyway. I am just gonna cut off a length and tap it. Instant bolt or nut. No tempering involved. Works. Even brass will work for a few moments or years if it isn't a lot of pressure against the threads. It is the other 20% of the time it becomes important. Okay the magnet sticks, it must be ferrous. Important when welding. I pick up pieces of scrap metal fairly often. Busted truck axles from old trashed dump trucks, big bolts, and sometimes I have no idea what it is. Got a short rod downstairs the magnet sticks for a second or two, then it drops off. What the heck is that? We know from experience that fingernails on aluminum feel different than fingernails on iron or steel. Give me a jewlers loupe and your pocket knife. I will maybe be correct if I say it is probably carbon 1040, or declare it to be a cheap stainless, but maybe not. The sparks from the grinder test helps, but it only gets us so far when identifying what kind of steel this is. Also some metals, the dust is poisonous (also potentially explosive.flammable) Got a purpleK extinguisher? Think 10 times before machining something with berrylium in it. Other types of metals can be bad too. Anyone else remember that old 1960s Tennessee tale about the volunteer fire department that had a funky hunk of metal they used as an anvil out in back? Lovely stuff, folks would gather around to watch when it was being beat on because with any hard blow it would emit a shower of sparks. Bring your wife, bring your kids. Everyone standing close and going oooo and ahhh at the fireworks show. One day the boys from the old Atomic Energy Commision showed up and took it away. Dug a pit and took all the soil that had been around the anvil too. No explanation offered. Draw your own conclusions.