There's another "Wand of Lightning" in the Planar Prison quest (one of the thralls has it).

For pearls, if memory serves well: When doing the "Illithium" quest for the Temple, Neb summons four spirits. When Neb dies, the spirits say something like "Free at last!" and each one drops a pearl...

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you can get loads of pearls by killing sirens.

You can get pearls from the Pirates' hideout in the Docks District as well.