I think he wants to know if a bag of unknown quality of rocks would be OK for his tank.
You need to find out what kind of rocks they are. You can't just throw in anything! They just don't have much personality if you ask me. Try breaking one up with a sledge hammer to give it some character (sharp edges and such) and do an acid test on it.
Planted tanks need a substrate that will allow roots to develop and be useful to the plant, that will hold the plant in place, and will also look good, plus, of course, not adversely affecting the water parameters. I don't think those pebbles would do it.