The term "jewel tones" refers to a group of rich, vibrant colors that are reminiscent of precious gemstones. These colors typically include deep shades of reds, blues, greens, purples and yellows, which evoke the beauty and radiance of jewels such as rubies, sapphires, emeralds, and diamonds. The phrase is often used to describe fashionable clothing or home decor items that feature these bold, saturated colors.