Just to make sure we've covered most of where they can be found:
•Look in the garden supply places for ground cover (2-5cm) and top dressing (<1cm-perfect for humidity/drip trays).
•Craft stores and flower shops may have them in the flower arragement supplies (<1cm)
•Aquarium supply sometimes has big chunks for tank decor and I think I saw the <1cm size.
•Barbeque/outdoor grill rocks are >2cm size
•Old volcanic formations could be whole mountain sides
__________________
Anon Y Mouse
"Never attribute to malice that which is adequately explained by stupidity." Hanlon’s Razor
I am not being argumentative. I am correcting you!