English: The three BlackGEM telescopes seen at the centre of this Picture of the Week, hosted at ESO’s La Silla Observatory in the Chilean Atacama Desert, are searching for the stuff that jewelry is made of. Developed by Radboud University, the Netherlands Research School for Astronomy, and KU Leuven, BlackGEM scans the sky looking for some of the most dramatic explosions in the Universe.When black holes or neutron stars merge with each other they create ripples in space-time called gravitational waves. These waves can be detected with sensitive facilities like LIGO or Virgo, but what if we could study the actual merger event in even more detail? BlackGEM can home in on the location of a merger by probing large areas of the sky in visible light, looking for the faint afterglow that may result from these cosmic collisions.When BlackGEM has found one of these sources, the true treasure hunt begins. These mergers are the factories of the heaviest elements in the universe, such as silver, gold and platinum: the jewels of the Universe. With larger optical telescopes, such as ESO’s Very Large Telescope further north in Chile, extremely detailed studies of the sources found by BlackGEM can be made, enabling astronomers to get a glimpse into how the heaviest elements are created.