Maybe factory rejects? When a monument gets fucked up during the engraving, they gotta do something with it...

Some people hunt rejected new (or disposed-of old) marble tombstones for pastry-making.

Could it also be old markers that are no longer being used? I can't imagine anyone would steal them...

At some point in the early-mid 20th century, all cemeteries were removed from within city limits of San Francisco. A stroll (!) through Buena Vista Park will reveal that many of the walkway gutters are lined with old tombstones.

I use them to cook pizzas on

My dad bought a crappy headstone for my mom in 1989 that eroded terribly. So we replaced it. The monument company said they turned it into gravel. Given that it was Oklahoma, I think they did -- heavy on the church righteous there. I wonder if other places aren't as diligent.

Obligatory:

https://youtu.be/Lh_W6FLaMvA

The Nazis used the gravestones of Jewish Poles to pave roads.

They messed up on my mother's gravestone. So my dad put it in the back yard under a tree. Grew up with that thing sitting back there all creepy, had to clean it with a scrub brush, it even moved with us once.

@4 They also used some of the headstones to form the seawall at Ocean Beach down near Rivera. Fun fact: Dolores Park used to be a Jewish cemetery.

We kept the headstone but threw away the body.

When they were building the Superdome in New Orleans, part of the site included an old cemetery. With the help of the Archdiocese they decommissioned it, deconsecrated it, pulled up all the tombstones and coffins they could find, and relocated them somewhere else. Then they built.

You can't prove anything, but you can't deny that the Dome was built with one of the end zones on the site of an old cemetery. Some wondered if this is why it seemed that the Saints football team couldn't win a fucking game for year after year playing in the Dome.