Utumno bricks are variants of brick found in Utumno. Each of the three levels has its own brick and associated glowing stairs, pillar, slab, and wall variants. As it is impossible to gain positive alignment with Utumno, these bricks are not craftable.
Ice Utumno bricks are blocks that generate in first level of Utumno. They are the main blocks of which this level is composed. The outside structure in Forodwaith, The Pits, is also made out of this type of brick. There are also occasional glowing bricks amongst the normal ones.
Obsidian Utumno brick slabs and obsidian Utumno pillar slabs do not generate anywhere in Utumno. They can only be obtained by using obsidian Utumno bricks and obsidian Utumno pillars on a vanilla crafting table.
Obsidian Utumno walls are a block similar to cobblestone walls, but they use the texture of obsidian Utumno bricks. They can only be obtained by using obsidian Utumno bricks on a vanilla crafting table.
All Variants of Obsidian Utumno Bricks.
What you could expect to see in a corridor in the second level of Utumno, before beta 33, although it will probably be much darker.
The fire Utumno pillars are blocks that spawn on the third level of Utumno. These pillars are purely for decorative reasons. This block can only be found in the fire level of Utumno, and is in no other way obtainable, meaning it is also uncraftable.