Scarce as they are, these two metals are necessary for our survival, playing essential roles in human growth and metabolism.
But one place we wouldn't expect to find either is clumped inside our brain cells.
However, for people with the neurodegenerative disorder Alzheimer's disease, something seems to be turning these elements into microscopic ingots.
A team of researchers from the US and UK spotted the tell-tale glint of copper and iron in their elemental forms using a form of X-ray microscopy (STXM) on samples of neural plaques taken from the frontal and temporal lobes of Alzheimer's patients.
Plaques are a typical feature of this particular form of dementia, made up of proteins broken down into what's known as beta-amyloid.
Trapped as a charged ionic form inside hemoglobin, iron is a handy way to transport oxygen around the body.
But this is the first time anybody has uncovered tiny pieces of copper in elemental form inside human neurons. »