What gives the gem amethyst its purplish color?

Amethyst gets its purplish color because of the presence of iron and other impurities in the gem, and their reaction to the gem's natural radioactivity. 

QuartZ is the the answer good luck

Your answer is d. silli hope this ! : ) i left an explanation down below if you need it: a sill forms when hot magma squeezes between layers of rock to form a hardened sheet of rock. a sill is basically a tabular sheet intrusion between old layers of sedimentary rock, volcanic beds, or in the direction of foliation inherent in metamorphic rock. the word sill means a concordant intrusive sheet.