If you are interested in a small LED and a ferro rod take a look at the BSA Hotspark and a Photon X-light. For less than $15 you can have two great pieces of gear.
Sure you can buy knockoff "fauxtons" but the real ones are not too expensive and very reliable.
I am not a fan of magnesium shavings; maybe better than nothing but pretty useless IMO. The Hotspark gives off nice hot sparks with the back edge of most blades. It easily ignites all man-made tinders and many natural ones too.
These two items are the beginning of a good survival set up whether it is worn around the neck or not.