Anything gatherable names itself when you aim at it. Press, and the taking takes time — seconds that belong to the resource, divided by your skill. If somebody else finishes it first, your action interrupts and tells you so.
Nodes
Some sources — an iron outcrop, a log pile — are worked rather than picked. Stand at one and your progress banks toward the next unit; walk away and the bank keeps. Full pockets stall a node rather than refusing it: free up space and the work resumes where it stood.