A Fire Marble Dome (also known as a rotating dome) is a rotating circular dome found on each island in Riven. Each dome has several D'ni symbols representing colors on it, with one being of a yellow color. The yellow symbol marks the color associated with the island you are on. These colors are then used to power the generator found on Temple Island, which in turn powers up the Fire Marble Domes, allowing a person to use the linking book within.
Each Fire Marble Dome spins endlessly until someone presses the button on a nearby telescope when it is correctly aligned with the yellow D'ni symbol. It then stops momentarily on that symbol and opens, revealing a linking book protected by a slider puzzle. Once powered, The Stranger can use these linking books to link to the 233rd age, where Gehn can be found.
When Atrus trapped Gehn within Riven without a linking book, Gehn began experimenting with ways to power a linking book, as he did not have the ingredients necessary for The Art to function properly without returning to D'ni. He soon discovered a way to write an age, though it requires a specific type of power. He then builds the Fire Marble Domes to protect his linking books to the age and to power them so he can access them at any time. However, he soon captures a Moiety, upon which he discovers a crystal, which when placed over the linking panel, allows him to link without power. He then abandons the domes.