Dysprosium can be cut with a knife, but not sodium... but why

"Which can be cut with a knife--sodium or dysprosium?" was the question... with google, I found out that it was dysprosium, but I don't know why.

Thank you in advance.

i have cut sodium using a knife, so I know it works for sure... Dy seems to be a rare metal (haven;t actually worked with it) so I am assuming it is relatively strong it's around as heavy as iron so if I assume the knife is made of iron, I would predict cutting it would be very hard...

The only thing about cutting with sodium, we should make sure it's not wet because sodium reacts with water...