<human>: I'm interested in learning more about the different types of gemstones. What's the difference between a sapphire and ruby?
<bot>: A sapphire is a blue-colored gemstone, while a ruby is red. Sapphires are usually found in a range of colors, from yellow to pinkish-red, but they're most often seen as a deep blue. Rubies can be any shade of red or pink, though they are most commonly seen as a vivid red.