Which type of a headband is in the picture?
A ferronnière is a style of headband that encircles the wearer's forehead, usually with a small jewel suspended in the centre. The original form of the headband was worn in late fifteenth-century Italy, and was rechristened a ferronnière at the time of its revival in the second quarter of the nineteenth century for both day and (more frequently) formal and evening wear.
The original ornament that later became called a ferronnière was popular in 15th-century Italy, where it could be made from metal or jewels.
The nineteenth-century ferronnière was worn from the late 1820s to the early 1840s, when it was considered to enhance a high forehead, and by the 1850s, it had fallen out of fashion. One contemporary source from 1831 describes the ferronnière as "a small plait of hair, adorned in the centre of the forehead by a large brilliant, from which depends another brilliant of the pear shape." It has been described as one of the most widely worn examples of historicism in early Victorian fashion, worn as a tribute to the Renaissance alongside beaded belts called cordelières inspired by medieval clothing and hairstyles named after historic women such as Agnès Sorel and Blanche of Castile. The ferronnière could be worn for either day or evening. Alternative terms for similar ornaments were the bandelette and the tour de tête.