Designer Signed Anton Mexico Mexican Sterling Silver Green Onyx Necklace - Pisces the Fish Pendant

Dating pre-1948 (no Eagle Mark) may I offer from Mexico this Sterling Silver (hallmarked as pictured) necklace.  Featuring a two fish (zodiac sign - Pisces) pendant above a hand hammered drop, the design is enhanced with 3 cabs of green onyx (or chrysoprase???) and is suspended from a very nice Sterling Silver belcher chain.  The pendant measures 2-3/4" x 2-5/16"; the chain measures 22" long.  Weight is 28 grams combined.  Wrought in the manner of a Margot of Taxco piece of jewelry, this is a very interesting example of vintage Mexican silver - not to be missed!