The Stacked Hardened Lava Wall is a dark muted maroon building-block with chiselled parallel lines on 4 sides and a smooth surface looking like hardened viscous lava on 2 sides.
It can be crafted in your Crafting Menu (default key "Q") or at any Crafting Table in worlds created before R22 on September 16th 2015, after the recipe has been unlocked upon buying it in the Store as a part of the "Decorative Lava Pack" (as of R24 in November 2015).
To craft 8 (blocks of) Stacked Hardened Lava Walls, you'll need (as of R24 in November 2015):
- 1x Melted Wax made of Beeswax in a Forge or looted from Wood Treasure Chests or Stone Treasure Chests
- 1 Iron Rod made of Iron Bars in a Processor or found in Iron Treasure Chests or in Diamond Treasure Chests
- 1 (block of) Igneous Rocks mined from the Lava layer, which requires at least a Diamond Mining Cell
- 4 (blocks of) Hardened Lavas mined from the Lava layer, which requires at least a Diamond Mining Cell