The following words have something in common. Can you determine what it is?

GEM
FIRST
PEACH
SILVER
GARDEN
GRANITE
MOUNTAIN

Answer:

They are all official nicknames of U.S. states:

GEM - IDAHO
FIRST - DELAWARE
PEACH - GEORGIA
SILVER - NEVADA
GARDEN - NEW JERSEY
GRANITE - NEW HAMPSHIRE 
MOUNTAIN - WEST VIRGINIA