18K Gold .50CT TW Diamond 18mm Mabe Pearl Snail Pin Brooch - French Escargot

Dating to the 1960s/1970s or so and possibly Made in France, may I offer this 18K Yellow Gold (hallmarked MDI 18 as pictured) pin/brooch in the shape of a snail - escargot in French. The shell of the body is made up of a mabe pearl while the main body and center dot to the shell are fashioned of faceted round white diamonds. The stone atop the shell measures 3.2mm (12 points) and is graded G-H with SI1 clarity. The pave diamonds along the body are set in white gold or platinum and number 31 (if my eyes are not deceiving me) - they range in size from 1 to 1.5 points for a total carat count of .32CT TW approx. Total diamond gemstone weight is about .45CT TW approx but I'm pretty sure the piece would have been sold as .50CT TW - a half carat of gems always sounds better. The mabe pearl measures about 18mm around and has a height of about 1/2". Total weight of the pin is 10.4 grams. Safety catch at the reverse to hold the pinstem in place. Size of the pin is 1-2/8" high or long x 1" wide. In looking on the Internet, there are so many interpretations of a snail pin - I could find nothing like mine. A rare find, indeed!