彩虹磚 is a 困難模式 磚 that can only be obtained as a drop from the 彩虹史萊姆 (only spawn during rain or a blizzard). They cycle through the colors of the rainbow. The cycling colors of 彩虹磚牆s, the 迪斯科球 and 彩虹染髮劑 are synchronized with each other. When a waterfall passes over a Rainbow Brick, said waterfall will also cycle through colors.
- Next to 叢林蜥蜴磚, Rainbow Bricks are one of the hardest blocks to obtain, being that they never occur in the environment, cannot be crafted, and only drop from Rainbow Slimes -- which only spawn during 雨 or 暴雪s near the 神聖. Despite this, Rainbow Bricks still only have a 稀有度 of white (second lowest only behind gray which only applies to trash items and white tier tools with negative modifiers).
- If you let water pass through rainbow brick by turning the brick into a half slab, it will cause the water to change color with it.
- The aesthetic of the brick, when placed, will either have the rectangular appearance of a standard brick, such as a 灰磚, or a uniform blank appearance, such as that of a 光面大理石塊. It may also change between one and the other when hammered. This can make it a rather tedious building material to use.
- 1.2.4：Rainbow Bricks and Brick Walls now go through the entire spectrum, rather than merely green-blue-red.