Yes, of course, stone doesn’t really grow back on the timescales that we care about. Yes, stone not “bio” in any sense really.
But the goal of the law is not to make biology or geology points. It is to reduce the embodied carbon of new construction. I guess the determination was made that stone has some carbon cost… maybe it comes from the mining?
Or maybe they are trying to kickstart, specifically, a new industry in the field of growable construction material. Maybe they figure stone mining is already well developed tech anyway.
Lots of house in France are made of that. Not “rocks” and that is a co2 intensive process to produce concrete.
See : Lafarge
Likewise, there's nothing renewable about stone. Our primary source is digging it out of the ground.
That isn't renewable in the timeframe of humanity, but in the age of the universe it's renewable.
You can recycle them. And raw stones are not a rare thing and they do get formed new constantly inside the earth.
I wouldn't call that marginal. And vulcanoes are just the visible part of that process happening everywhere in the crust.
Some rate of formation is not enough to satisfy the commonly held definition of renewable resources. Google "is stone a renewable resource" for a jumping off point.
Sure, it doesn't fit the definition, but there is also no reason to care that it doesn't.
(Concrete isn't, but plain old stone? Or bricks?)