I'm really not sure what this stone is, but it sure is complimented well by the copper. Sometimes it looks bluish, sometimes, more turqoisey...depends on the light and its surroundings. It's a nice big pendant - almost 3" from the top of the bail to the bottom of the stone.
Turquoise-like Marquise Stone in Copper
Tallest & widest dimensions
2.8 x 1.4 inches or 70 x 35mm
About the copper
I used pure copper wire, oxidized it to achieve a timeless "antiqued" look, and then polished, cleaned and sealed the piece, so that the copper will never tarnish any further or rub off on your skin.
You won't need to polish your pendant, just keep it protected from scratches and bumps against hard surfaces or other jewelry.