Help growing unknown succ. leaf

Hi everyone, hopefully someone can help me out!

I found (yes, found) a somewhat healthy leaf of a succulent which I took home. I wasn't worrying too much about it, but since it hasn't died yet it's become a sort of side-project of mine to try and save it. I think it may be an echeveria, but I haven't seen it anywhere. I've had it for a few weeks now but it hasn't rooted itself. It seems to have been cut quite cleanly and high up on the leaf, not where it would attach to the plant itself (if it had fallen off naturally). A few brown thingies have poked out of the cut end of the leaf but haven't really done anything as of yet.
The leaf itself is shrivelling up and it looks like it's about to die. I don't want to water it yet until it grows some roots, since I don't want it to rot.

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Here's some photos - Hopefully you can see how it has been 'cut' and the brown bits poking out the end (close to the middle). That round spot in the middle of the leaf was not visible at first but as the leaf shrunk, that spot didn't, so now it stands out like a blister.

Can anyone help me save this thing before it dies? I'll be willing to send a cutting to anyone who can help me (once it establishes itself), or is this leaf too far gone?

Dunno about this, I think it most likely will die. Some succulent leaves will offset roots better than others.

You might be able to use a root hormone to stimulate root growth, other than that I'm not sure.

I see. Oh well, thanks, I guess I'll hope for the best. I'll start a thread over at the ID forum to see if anyone can help identify it - if its an easy species to acquire it may be better just to buy a healthy plant.