Solder
The alloy used to join two pieces of metal with heat. Every join in a piece of jewellery is a solder seam.
Jewellery solder is matched to the metal and comes in grades that melt at different temperatures, so several joins can be made near each other without the earlier ones reopening.
A good seam is invisible after finishing. A visible line, a pit or a colour difference indicates a poor join.
Older Indian gold sometimes used cadmium-bearing solder, marked KDM, which is now banned on health grounds.
When you are buying
Look closely at where a bail meets a pendant and where a shank meets a setting. Those are the joins that carry load and the ones that fail.
Annealing
Heating metal to soften it after working, so it can be bent further without cracking.
Jump Ring
A small metal ring joining two parts of a piece. The commonest failure point after the clasp.
Shank
The band of a ring, everything except the setting and stones. Where resizing happens.
Bail
The loop connecting a pendant to its chain. Its inner width caps what chain the pendant will fit.
916 Gold
The hallmark number for 22 karat gold, meaning 91.6% pure. The same thing as 22K.