Sounds like the sort of session that'll be talked about for years by those involved. Nicely done!
Lan-"this is true of many a PvP session, IME"-efan
It's entirely possible to get fossils made of extremely hard minerals that are far from fragile from real world creatures. Additionally something like dragons or the tarrasque would have to have bones way beyond anything ever found on earth.Fossils are fragile, so the bone cannot be an artifact of a Truly Ancient Evil. Then again, it's magic...

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.