Socket or tang, and section.
Note whether the head has a socket or a tang, its cross-section, and any barbs. These features separate periods and regions more reliably than size does.
In flint, the classic sequence runs leaf-shaped (Neolithic), transverse (later Neolithic), and barbed-and-tanged (Early Bronze Age) — each distinctive at a glance once seen. In iron, a long slender bodkin point and a broad flat hunting head are different tools with different dates.
Iron heads survive as corroded shapes and often keep mineralised wood from the shaft inside the socket — do not clean it out; it is evidence.
Beware modern reproductions cast or knapped from originals; fresh flake scars on an otherwise patinated flint are the usual giveaway. Record section, fixing method, and dimensions, and let the typology assign the period.
Identifying swords and daggers