From eBay.
This miniature appears to be based on the von Neff portrait in the preceding image.
Keywords: Tsaritsa Alexandra Feodrovna (1798-1860), Hohenzollern family, Romanov family, Tsaritsa, Russian, hurluberlu coiffure, crown, off shoulder vee neckline, modesty piece, Russian sleeves, vee waistline, order sash, order star, necklace, jeweled bodice