ANTIQUE GUILLOCHE ENAMEL order brooch

THIS IS A STUNNING BEAUTIFUL BLUE GUILLOCHE ENAMEL BROOCH . THE ENAMEL HAS BEEN LAID ONTO A RADIALLY ETCHED SILVER BASE, SURROUNDING A RAISED CENTRAL OVAL OF WHITE ENAMEL. THIS IS FRAMED BY A RING OF WHITE ENAMEL, WHICH IS SURROUNDED BY EXPOSED OXIDISED order SILVER DECORATED WITH A SCALLOPED PATTERN. IT APPEARS TO HAVE A SILVER GILT BACK - SOME OF THE GILDING HAS DETERIORATED . THE REVERSE IS STAMPED '750' AND 'G ST'- POSSIBLY INDICATING IT IS 18CT GOLDON STERLING SILVER - BUT THAT IS JUST A GUESS. THERE IS ALSO ANOTHER INDISTINCT MARK CENTRALLY, WHICH MAY BE THE MAKERS MARK. I HAVE LISTED THIS AS THE DANISH JEWELLER S.L.JACOBSEN. I CANNOT BE 100 PERCENT SURE BUT IT APPEARS TO BE VERY MUCH LIKE HIS WORK. MEASURES APPROX 24MMX16MM
IT IS A STUNNINGLY BEAUTIFULLY AND WELL CRAFTED BROOCH AND THE BLUE GUILLOCHE IS AMAZING. THIS LITTLE BROOCH IS QUITE LITERALLY BEAUTIFUL . I WISH I COULD SAY FOR SURE IT IS BY JACOBSEN, BUT CAN ONLY ATTRIBUTE IT TO HIM. THE C CLASP WORKS WELL TOO.