Red, green and yellow bell pepper but haven't heard of a purple one?
Here it is:
|Purple Bell Pepper|
It is just about the size of a thumb. All I know it is for ornamental purposes only but lately I found that these are also edible.
Here are some details of the said plant Taken from ArtFire.
"Heirloom Chinese Five Color pepper starts out a deep blue-purple, turning to mauve, creamy peach yellow, bright yellow, orange and fully ripening to red. Chinese Five Color Pepper is a prolific producer of small fruit up to 3/4" by 1 1/2" that grow upright on the compact plants. The fruit are shaped like small Christmas light bulbs. The upright bushy plants get about 18" in height. The stems and branches don't get very big in diameter but they are strong (not willowy) and somewhat shrub like. The five petal blooms have light purple petals with white centers and darker purple colored stamens. Ornamental and edible pepper!! We suggest to keep these in containers or elevated in a rock garden. Keep your Chinese Five Color Pepper in a container and you can bring it inside in the winter and have it for years. Packet contains approximately 25 seeds grown naturally with love and care. 80 days until fruit."