Answer:

emeralds

Answer	Crossword Clue
EMERALDS	MAY
EMERALDS	May birthstones
EMERALDS	Some sights in Oz

EMERALDS	Things mined in Cleopatra's Mines
EMERALDS	Green valuables
EMERALDS	Green gems
EMERALDS	Green rocks
EMERALDS	Colombia is their largest producer
EMERALDS	Stones in crowns
EMERALDS	Beryl varieties
EMERALDS	Some hummingbirds

EMERALDS	Bright green hummingbirds