In the damaged area of the third photo you get a look inside and see a number of small cavities that are empty (rather than being filled with powdery spores). What you have is one of the native truffles with rusty brown spores, so I'd guess one of the truffles related to a mushroom genus such as Cortinarius or Descolea. I may have handled this species at some time, but can't immediately think of a possible genus for it.