Crumbs, it appears that last Friday’s object stumped everyone! Harrison certainly chose a difficult one…
SmallCasserole came closest, asking:
Is it antler or horn?
but my response:
Antler or horn that thick?
was perhaps too ambiguous – because there is a horn out there that is this thick, that of a rhinoceros.
The fibres that Carmenego spotted are the compacted hairs that rhino horn is composed of, and the horn core that SmallCasserole was expecting does exist – just not in this section, which is taken from just a bit higher up the horn.
Some good deductions there – you just missed the coup de grace! An easier one this week perhaps?
Zygoma 
I do think you should mention that you showed the pictures round, just on your gphone, at a family gathering yesterday and your aunt and cousin, neither of whom has any science training whatsoever, got this and earlier #FMOs almost instantaneously.