I am not totally sure what this stone is. My best guess is Moss Agate. Framed it quite elaborately...
Comes with a 24" faux-copper chain.
Moss Agate (?) Round
Tallest & widest dimensions
2 1/2"x 1 1/4"
About the copper
Antiqued, polished and sealed. Will not darken further or rub off on skin. No polishing needed.