This is a beautiful copper and agate pendant with copper chain. 
The agate has been electroformed with copper. 
It measures 2” x 1 3/8”
The chain is 20” long as has a toggle clasp. 
So nice! Copper has many healing benefits and is very grounding. 
The copper will eventually over time change in its shine, polish and May have a nice patina, or green hues. You can polish it back up to its shine with a copper polish cloth.