Mycobacterium vaccae (The Golden Bacillus), is a ubiquitous and natural soil bacterium that you are likely to ingest or inhale when you spend time in natural environments. In mice, exposure to this bacterium has been shown to stimulate the growth of certain neurons in the brain, resulting in increased levels of serotonin, and through this decreased anxiety. In addition to this, mice which have been fed live M. vaccae navigate mazes twice as fast as controls suggesting that exposure to this bacteria may also improve the ability to learn new tasks. Here, cultures of M. vaccae have been processed into novel crystalline forms, which are the basis of a novel concept for BioGems. These will later be incorporated into a range of provocative probiotic jewellery, that not only looks attractive, but might also improve the health of the wearer. Other applications might include BioSequins for probiotic attire, and also probiotic body creams and perfumes.