Any idea what this is?

I'm doing a complete overhaul of my yard and I have a 10x10x30 piece of stone that looks like a pedestal. Anyone know what it is exactly and what I should be looking to sell it for?

Looks like marble. Was probably gonna be a tombstone?

It would make a nice roadside marker.

"You are halfway there".

Mile stone ? Is what I thought too

Where on the property did you find it? Around here (New England) similar stones were often used as property line markers - though the ones here tend not to be curved on the top, just flat.

That appears to be a boundary marker, the shape is right as is the material, it would be used to mark the edge of a property, county border line, state boundary (border) Line.

I also found some civil war era head stones in that same shape in our oldest cemetery.

Just judging from the current appearance I would be most inclined to call it a boundary marker though.