Minecraft wiki entry for Void, associated text: In Beta 1.8, black void fog and the depthsuspend particle effect were introduced. As the player descended below Y=17 in the Overworld, the void fog and particles would start to appear. As the player traveled deeper, the fog at the edge of the render distance would become closer until the player reached bedrock, where visibility was reduced to just a few blocks, beyond which was complete darkness. The gray void particles appeared below Y=17, as well as in the void.