This item is a Vintage Large Oval or Egg Shaped Faux Turquoise Pin, Brooch, Scarf Pin.  It has the faux Turquoise all the way around the piece.  The Turquoise color "could be" enamal.  It is not true Turquoise.  

The frame of this item is of a Gold colored material.  I do not think it is real Gold because of the pitting and the tarnishing that is on it.  But A MAGNET DOES NOT STICK TO THIS PIECE OR PARTS OF IT.   It could possibly be of a silver coated material.  I am not an expert on jewelry.  I picked this piece up at a flea market back in 2003.  I wore it as a scarf pin when I worked in an office.  

The lever that the pinback goes into has ridges that you have to flip down with a fingernail or tip of your finger.  Then that lever snaps back into place.  It holds the pin into place where it should be.  The pin is straight and is rather thick.  One could wear this piece also as a pendant as the pin is so close to the shephards hook type piece so the chain wont come off or out.  

There is pitting to the gold areas that cant be scratched off.  

Measures 2 3/4 inches wide x 1 11/16 inches tall x 1/2 inches thick.  A nice piece ... the enamel is not cracked and the pin brooch is solid and not bent