As Wiki puts it, Steampunk is a sub-genre of science fiction, alternate history, and speculative fiction that came into prominence during the 1980s and early 1990s. This style involves an era where steam power is widely used- the 19th century. Fiction and fantasy, fashion, architecture and art in the Victorian times, that’s what characterize steampunk.
Also, steampunk was influenced by scientific romans of Jules Verne or Mark Twain. The pieces are very crafted and the materials used are: polished brass, iron, wood, and leather. Steampunk jewelry are
both antique and futuristic. I have found these steampunk jewelry in some folders on my computer but unfortunately I could not find the source or the name of the designer. If you know it, please let me know. Thank you! Otherwise, if you really are interested in this kind of jewelry, here they are two artists that create steampunk, on Etsy. You can find their shop here and here.