Copper Knife

A copper knife is a hammered native-copper blade with one cutting edge (two in the dagger-like form), usually with a tang, a socket or a grip hammered in one piece with the blade. West (1929) sorted Wisconsin knives into curved-back, straight-back, one-piece handled, socketed and double-edged leaf-shaped forms; socketed and double-edged knives often have rivet holes for pinning a handle. Crescent (semilunar) knives are curved blades, sharp on the outer edge and blunt on the inner, with or without upright prongs.

Makers cold-hammered and ground the copper, annealing it to stop it crumbling, and bevelled the cutting edge; some blades were cut from sheet and never sharpened (West 1929). A crescent repaired in antiquity shows hammering, annealing and punching (West 1932).

West (1929) read most crescents as hafted chopping knives, scrapers or hide-dressing tools, comparing them with the slate crescent knife used by Inuit women in the 1800s; the Milwaukee Public Museum notes that crescent edges are generally blunt and that their use, as tools or as neck ornaments, is debated. After spear and arrow points, knives are the most common copper class in Wisconsin (West 1929). The key trait is a hammered copper blade with a single bevelled edge and a tang, socket or one-piece grip.

Curved-back knives 25–305 mm long; straight-back knives 105–203 mm; crescents 76–229 mm across the blade (West 1929, Wisconsin, converted from inches). The Milwaukee Public Museum's roughly 100 knives are 40–320 mm long. The largest knife-like piece reported from Wisconsin is 445 mm overall with a 162 mm tang (West 1932).

Core area: Wisconsin and northern Michigan (Keweenaw), concentrated in east-central Wisconsin near Lake Winnebago, and spread through the Great Lakes by trade (Milwaukee Public Museum). Edges: one-piece handled knives from Manitoba and North Dakota (West 1929); Old Copper types in Ontario (Milwaukee Public Museum).

Look for a one-sided bevelled edge and a hafting element: a tang, socket or rivet holes. Copper spear and arrow points are symmetrical and pointed for a shaft (Library type Copper). Copper spatulas are flat bevelled blades with no knife edge along one side (West 1932), and copper celts have their bit at the end rather than along the side. Pronged crescents carry two upright prongs from the inner edge (West 1932). Chipped stone crescent knives share the outline but are flaked stone. West (1929) counted many crescents among Wisconsin finds; the Milwaukee Public Museum still treats their function as an open question.