Fine gilded sterling silver black guilloché enamel necklace. Necklace dates to the 1950s and originated in Norway by David Andersen. The enamel panels alternate between larger and smaller with solid black enamelling with a delicate white guilloché flower in each smaller panel. Guilloché is a decorative engraving technique in which a very precise intricate repetitive pattern or design which is mechanically engraved into an underlying material with fine detail. Specifically, it involves a technique of engine turning, called "guilloché" after the French engineer "Guillot," who invented the machine "that could scratch fine patterns and designs on metallic surfaces." Also called a rose engine, this machine improved upon the more time-consuming practice of making similar designs by hand, allowing for greater delicacy, precision, and closeness of the line, as well as greater speed. The necklace is 15" ( 38 cm) long when closed with a push in style catch. The width is 1/2" (1 cm). Stamped in 2 places: David Anderson, Norway along with 925 S. Enamel is mint condition; with no damage, dings, chips, cracks, enamel loss or repairs. The underside of the necklace has been gilt but showing some time enhanced patina. This can easily be buffed out with a polishing cloth if desired. A striking piece and not often seen black enamel example.