Final answer:
Beryl, emerald, and aquamarine are different varieties of the gem beryl, each with different colors due to impurities. Beryl is colorless, emerald is green, and aquamarine is light blue.
Step-by-step explanation:
The different varieties of the gem beryl, such as beryl, emerald, and aquamarine, vary in color due to the presence of different impurities. Beryl is typically colorless, while emerald is green and aquamarine is light blue. The colors of emerald and aquamarine are caused by the presence of small amounts of Cr³+ impurities in the crystal structure, while beryl does not contain these impurities.