Bismuth crystals reflect light in all colours of the rainbowOliver Berg/dpa/AlamyUltra-thin flakes of bismuth display mysterious magnetic properties which could help the soft, iridescent metal become a wonder material for making greener electronics.Frankly, Im still waking up at night because I wonder: what is at play here? says Guillaume Gervais at McGill University in Montreal, Canada.Researchers have suspected that very thin flakes of bismuth could have unusual physical properties, as other ultra-thin materials like carbon-based graphene do. But because bismuth is so