Argentium Silver Teardrop shape Lobster Clasp with fixed ring incorporated.
Approx. 9.1mm length.
Argentium Silver is slightly different to Sterling Silver in that it modifies that alloy by replacing some of the copper with germanium. As it contains at least 92.5% silver content of the traditional alloy, it is still referred to as sterling silver and meets the hallmarking requirements for the U.K. Britannia standard.
The addition of germanium means that Argentium is extremely slow to tarnish which is a great benefit to jewellery makers! Wikipedia has a good explanation of Argentium Silver for those wanting further information.