[Tuj] YES! Our mystery man was in fact the notorious pirate Edward Teach (or Thatch, or any of a variety of other creative 18th century spellings), aka Blackbeard.
He probably acted as a privateer during Queen Anne's War and subsequently turned pirate. Killed in battle in 1718; his Wikipedia article suggests that the governor of Virginia overstepped his authority by sending troops into North Carolina to attack the pirates, hence the doubtful legality.
One baton in the shape of a yard-arm with a severed head hanging from it goes to Tuj.

[jim] It was your answer to "begins with P", hinting at a pseudonym, wot dun it.
So! let's have a bit of

MINERAL

.

NO and NO =)

Tell me, Master Tuj, this mineral object that you have chosen, would it happen to commence with the 16th letter of the standard English alphabet?

[CdM] INDEED 'TIS SO! And yea surely with such insightful queries from the outset ye are halfway there!

Radioactive? NO
Pu? NO
Pr? NO
Is this unknown item/items numbered? NO, not that I know of
Pluto? NO

Stone? NO, though it surely contains some
In a particular place? YES *couple of disparate claps from the audience, and some talking*
Unique? YES ("object", maybe)
Man made? NO

On or part of Earth? YES
In a single country? YES
Geographical feature? YES
Pluto? NO (again)

Larger than? We always have trouble with these questions, don't we? I'm pretty happy to give a YES, though not uniformly
Moving around? EUGH um... in the sense you probably mean, NOT MUCH, though in a different sense the answer would be YES

Watery? YES *audience applauds*
Pluto? ...still NO I'm afraid *audience all sit down looking disgruntled*
River or part of? YES! *standing ovation*

Platte? NO
European? YES