The museum recently acquired twelve "haunted" paintings, none of which have been properly cataloged yet.

To join the two clauses without using a conjunction (like "and"), we must use a relative pronoun. "None of them" would create a grammatical error called a comma splice. Since "paintings" are things, we use "which."

I also found three antique dolls in the basement, two of whose glass eyes seem to follow me around the room.

We need a possessive relative pronoun here because the "glass eyes" belong to the dolls. "Whose" is the only relative pronoun that indicates possession, and it can be used for both people and things.