Vintage Tubogas necklace circa 1960-1970

Often between 1936 and 1950 the necklaces were made of a mesh called "gas pipe or tubogaz" or also called snake mesh.
But it seems that it dates back to 1932, and the Italian jeweler Bulgari would be one of the first to produce them.
"The first serpentine-looking jewels appeared at the Roman jeweler's. They were called "Tubogas," in reference to the industrial aesthetic in vogue at the time."