A rock called peridotite produces which hardest of gems?

What is a ring-shaped cake pan with fluted sides called? A river in which state is named for the Rappahannock tribe that John Smith met in 1607? A river is named for which Scottish-born explorer, the first European known to cross North America north of Mexico? What phrase means a robbery at gunpoint or an adhesive air freshener? Which group recorded "How Deep Is Your Love"? A relationship with exotic dancer Fanne Foxe ended which powerful congressman's career in 1974? Which 1889 Mark Twain novel sends a 19th-century American back in time to Camelot? What word names a roll of fabric or an arrow from a crossbow?