The Blue Diamond — Joan Smith

She was lovely, the German heiress, Maria. She had the grace of a swan and the face of an angel. But she found the Englishman, Lord Moncrief unsuitable. Fascinating, but unsuitable. Too bold. Moncrief, for his part, appeared to prefer the enchanting and mysterious young Frenchwoman, Mademoiselle Feydeau, whose secret cache of jewels was arousing much interest among the international aristocracy. Suddenly Maria did not find him so unsuitable... Against the background of Vienna's high society at the time of Napoleon's escape from Elba, this tale unfolds an unusual love story filled with danger, romance and dazzling intrigue.