Minecraft wiki entry for Beacon, associated text: The color of the beam may be changed by placing blocks of stained glass (or stained glass panes) anywhere above the beacon block. The beam changes colors according to the colors of glass placed above it: the first block sets the beam color, while each additional block sets the color by averaging the red, green, and blue components of the current beam color and the block's color. The color values are the same as those for the corresponding dye. This also works using hardened stained glass and hardened stained glass panes.‌[Bedrock and Education editions only]