Mosser Lee River Gravel/Pearl Stone

[Wolfn]

I have a Cephalotus planted successfully in peat/sand mixture and has been thriving the past year. I want to add a decorative soil cover of some sort of stone. My local hardware stores sell Mosser-Lee River Gravel and Pearl Stone. Would these work, or are they too alkaline (limestone)?

I've looked around and can't find anything that says what sort of rock they are. Does anyone have any experience with them?

 

[Wolfn]

Anyone?

 

[SubRosa]

Put it in some vinegar. If it fizzes, no good it's limestone