As I wrote in my previous post 'Nineteenth Century Day Jewellery', women of the nineteenth century were constantly instructed not to wear 'showy' jewellery during the day, often on the grounds of taste, marriageability, and morality.
One way women who wanted to wear jewellery but still be 'in good taste' could get around this problem was by wearing ornaments that served a purpose - Chatelaines.
Chatelaines were originally the keys to the castle, worn in earlier centuries by the Lady of the castle, then later by the housekeeper of great houses. At a time when pockets in women's clothing were seen as symbols of privacy and secrecy, and depicted in paintings to symbolise a woman's private (sexual) life and therefore her immorality (!), the keys to the castle were worn on a chain fastened over the clothes around the waist. N.B. - I'd intended that to be a shorter sentence, and to provide a single link to explain. Turns out this is a larger topic than I'd remembered, and a single link won't be enough. Try here, here, or here, for some good articles on the history of women's pockets.