Age

An Age is a Minecraft dimension generated by Mystcraft.

All ages will have Abandoned Libraries. Various features, such as caves, ravines, villages, etc., may be found, and potentially at higher frequency than in the vanilla overworld. Or, they might not be found at all.

Most ages will not have vanilla-like biome layouts. Ages may have biomes that cannot normally be found in the vanilla overworld (this requires having biome-adding mods that do not put their biomes in the overworld). Rivers, Oceans, and "border" biomes -- shores, edges, beaches, etc. -- will be the biggest changes from normal.

Lands may be "normal", or they may be flat, caveworld (nether-like), void, etc.

Skylands can be found in any type of world, and will generally carve the world into large numbers of small islands.

Unstable ages may have Instability.