Dark Ashes is a dust added by TechReborn. It is a byproduct from several recipes.
Crafting Table recipe:
Blast Furnace recipe:
Iron Ingot + 2xCoal Dust → Steel Ingot + 2xDark Ashes
Steel Ingot + Tungsten Ingot → Hot Tungstensteel Ingot + 4xDark Ashes
Industrial Centrifuge recipe:
16x Basalt Dust → Peridot Dust + 3xCalcite Dust + 8xFlint Dust + 4xDark Ashes
Industrial Electrolyzer recipe:
4x Blaze Powder → Dark Ashes + Sulfur Dust
Implosion Compressor recipe:
Dark Ashes is a byproduct from every recipe with Tnt usage.