Heh, it happens to all of us occasionally (well... maybe not Shien). I'd honestly forgotten about it myself until I started doing some research on magma and iron to determine whether magma would be hot enough to melt it (what I discovered: sometimes) and just happened to spot the melting point of carbon-based steel while reminding myself of that of iron (the only element I remember the boiling point of by heart is gold, simply because it's 1337 degrees Kelvin (approximately), which is funny).
Besides, Jillian's father was a silversmith/goldsmith, was he not? If so he probably didn't work with iron or steel a lot...