Emerald is the bluish green to green variety of beryl, a mineral species that includes aquamarine.
The most valued variety of beryl, emerald was once cherished by Spanish conquistadors, Inca kings, Moguls, and pharaohs. Today, fine gems come from Africa, South America, and Central Asia.
A ruby is a pink to blood-red colored gemstone, a variety of the mineral corundum
Rubies have always been held in high esteem in Asian countries. They were used to ornament armor of noblemen in India and China.