Resource nodes come in pure, normal and impure tiers.
Output
Pure gives double, impure gives half the base miner output for the same node.
Planning
Build your biggest lines on pure nodes and save impure for side needs.
Tip
Use overclocking to squeeze more from a lower-purity node when pure is taken.
Practical notes
Purity decides how long a node feeds your line before you need a second one. A pure node gives double the base miner output and an impure one gives half, which means an impure site needs twice the machines to serve the same line.
Build your biggest lines on pure nodes and keep impure sites for side projects that do not need volume.
Overclocking can close part of the gap on an impure node, but it costs power shards and grid capacity, so a second pure node usually wins. Check the map before every miner placement, because the node you skip today is the one you relocate for tomorrow.
Mark reserved nodes with signs so later expansions know what is taken. When every nearby pure node is claimed, the honest answer is a longer belt to a fresh site, not a bigger factory on a depleted one.
Node purity also shapes overclocking decisions. A pure node leaves more headroom before the miner needs shards, so save shards for impure sites and late bottlenecks. The map tool shows purity on every node, and planning miners from the map beats flying out to inspect each one.
A pure node claimed today is a rebuild you never have to do next week.