I don't have a micrometer handy, but with my trusty scale I measure the blade thickness at about .135". The back of the blade is full width to within .56" of the tip. Plenty sturdy, in my opinion, and feels good in your hand too.
Be aware that the advertised blade length varies quite a bit from site to site, some up to 4.25". Mine is 3.75", the length given by Buck.