There is an Agnolo Tori (though I've also found it as Bronzino) one that appears to be in red silk, has the proper square neckline but the embroidery doesn't match (doesn't have the double line down the front). There are two more from il Bronzino, one red and one dark (possibly black) but in both she's wearing a jacket with embroidered center, which could be interpreted as the double line, but I think that would be pushing. Haven't been able to find anything else that matches yet, except for a couple of mentions to a miniature painted by Giulio Clove that I can't find :)

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