I’m willing to bet that the Shroud of Turin is at least as authentic as a religious relic as the ‘magic rock’ in the black cube in Mecca.
It is believed, in Islam, that the rock and some other objects there constituted a device previously identified as Abraham's Altar.
The black rock is, itself, embedded in a stainless steel bracket. The bracket was devised some time in the Middle Ages when the Arabs developed stainless steel (easy to do if you have iron/nickel meteorites around).
This device is housed in a structure with a large black curtain around it.
Many people believe the large black curtain and the structure to be, in fact, a rock. They are not. The rock is far smaller. I have several neighbors who have touched it.