Just inside the main entrance of the Church of the Holy Sepulchre in Jerusalem is a large fractured stone, glimmering in the light of several overhead lanterns. When I first walked into the church, I thought this was the tombstone of Jesus, and all the people bent over it were revering it as such. I was close, but not exact.
This is the so-called unction stone, the slab where Jesus's body was purportedly anointed with oils before being laid in the tomb. Evidently, it's still being oiled on a regular basis, because it is shiny to the eye and slippery to the touch. As you can read in the linked Wikipedia article, the first mention of the stone on this spot wasn't until the 13th Century, and the current stone was only placed there in 1810.
There was a persistent line of pilgrims waiting to kneel before the stone and place their religious objects on it. Medals, icons, chains, candles, books all took their turn soaking up a little of the holy oil.