Jump rings are (usually metal) rings used to make chains, jewelry, and chainmaille. They are made by wrapping wire around a mandrel to make a coil, then cutting the coil with wire cutters to make individual rings. The rings can be assembled one by one into chains, earrings, objects such as bowls or ornaments, and chain mail clothing.
The making of items from jump rings is called chain maille (“maille” is French for “mesh”).
Jump rings can be described by the following qualities:
The thickness of the wire the ring is made from. Usually measured according to American Wire Gauge standards or in millimetres, but SWG (Standard Wire Gauge) may be used.
Approximately the same as the outer diameter of the mandrel used to create the rings, but the exact inner diameter will depend on the degree to which the wire springs as it comes off the mandrel.
The gap between the ends of the jump ring created by the cutting process.
Saw cut or pinched. The former produces a clean uniform cut whereas the latter is pinched and looks less attractive.
The outer diameter of the ring. This is the same as (twice the gauge + the inner diameter).
For example, anodised aluminium rings come in many colours.