On a recent afternoon at Tiffany & Co.’s jewelry studio in Manhattan, a dozen or so jewelers filed down gold engagement rings while a tiny vacuum installed at each of their workstations sucked up the gold dust to melt it down and recycle it. It’s a slow, meticulous task, in many ways little different from the process artisans have followed for hundreds of years.

At each station, there’s a small wood block, with a V-shape carved out in the middle, that’s attached to the worktable just below eye level. It’s called a bench pin, and the jewelers place the rings there to file them down. The bench pins of the more experienced jewelers are so worn that they almost look like pieces of driftwood. But some have few grooves, a sign of the tenure of their owners: apprentices.