Please help me with these markings on this gold chain clasp.

[jskoski]

Can anyone identify the markings? I think the 12k means 12 karat gold, but I'm not sure what the other marks are, or if I'm right about that even.

Also, has anyone seen the attached locket before?

Thank you!!

[bojibelle]

It is 1/20 12kt gold. Gold filled 1 part gold, 19 parts not gold. Not considered to be karat gold.

[zienty]

Many times lockets are on replaced chains. You should look for marks ON the locket.