Blue LEDs are usually manufactured in
clear cases using gallium nitride. There are
narrow beam bright ones that you can find in those personal LED flashlights, and dimmer ones that
radiate all around, most often used as indicator lights in
home electronics.
Blue LEDs are
COOL. I've changed my PC's case LEDs, my keyboard's LEDs, my main
C-64's LED and even the
LCD backlight on my other
cellphone.