Will these rocks raise the PH my betta tank?

Hi all!

I picked up some really sweet rocks (which I believe to be "elephant skin stones", though they were not labeled) yesterday, cleaned them, and added them to my tank. The LFS staff said that this stone won't affect PH, but I am concerned after doing some research. Some sources say these stones are not good for freshwater tanks, while other sources say they are very popular inert stones. I've also seen these stones in tanks with soft-water species??

Can anyone confirm whether or not this stone is inert, and if it will significantly impact my water chemistry? I love the look of them and really hope to keep them. For reference, my current parameters are as follows:
pH: 7.0
KH: 40ppm
GH: 120ppm

KH seems a little low but I'm not too sure.

Thank you!!

Update: I just pulled out a stone, scratched up part of it with a pair of pliers, and poured a little white vinegar on it. I know vinegar is a weak acid, but it didn't fizz. I guess they also look a little like ryuoh or seiryu stones, as well? I really have no idea

The simplest way to check is set up two containers with water in. Put a stone in one of them. Test the pH of both every day, and GH and KH if you have testers for them. The water without the stone will show any changes due to just the water standing. If the water with the stone in is different from the water without the stone, the difference is caused by the stone.