Blue Pigment is a crafting ingredient that can be processed and found, but not placed into the world nor into a quickslot, since it cannot be consumed.
Blue Flowers can be plucked from nearly every pine-like Elderwood-tree and over time slowly "regrow" on Elderwood Leaves too, even on Snowy Elderwood Leaves. They do not require any Power Cells to be harvested.
Blue Flowers can also be collected in significant amounts from Wood Treasure Chests that spawn on the surface and on surface layer blocks only at ingame-nights in complete darkness. Sometimes, Blue Flowers can be obtained from Blizzard Chizzards when killing them or taming and then harvesting from them as Pets.
To multiply Blue Flowers, it is sufficient to place blocks of Blue Flowers and pick them up repeatedly which will occasionally yield additional Flower blocks.
It is an ingredient in the following recipes:
Creating or finding Blue Pigment is one of the unlocking requirements for the crafting recipe for Blue Concrete and other crafting recipes.