There are Plenty of members that have used backyard / river stones. All the stones I have in my tank are from the neighborhood, and by where I work.
I inspect to ensure they don't have large fractures, bring them up to a boil, then after 10min, I let it cool back to room temp. I don't remove the rock from the boiling water.
75g Planted Barbs Denison, BlackRuby, Tiger, Albino Tiger, Green Tiger, Cherry, Gold, Checkered, Odessa.
NonBarbs Cardinal, Neon, RummyNose, Bloodfin Tetras, Z. Danios. 1RTS. Amano, Bamboo, Ghost & RCS. 20g Long Shrimp Tank RCS, Tiger, Amano.