Not sure if it is solely Brooklyn but minerals without any major modification to their form seem to be the choice material for several jewelry designers, myself included. I've seen pieces with Pyrite gold or black, Crystals and Howlite but my favorite (and one I've seen the least) is most definitely LAVA! I purchased some last week and will be tinkering with some new designs in the coming weeks... Be on the look out for new stuff on trinkknacks.com