My tortoise used to eat rocks...they usually eat this stuff if there is a lack of minerals in their diet. I bought Minerall that I sprinkle on top of her food twice a week and replaced her substrate so there were no more little rocks for her to eat.
as previously stated eating dirt/rocks is a sign they're lacking some sort of mineral in they're diet and trying to make up for it which could lead to becoming impacted i'm not sure of the name of the stuff but i also think it's just called minerall to as post above me said
My Desert Tortoises were eating dirt and I bought some Miner-All. I sprinkle it on their food once a week and they stopped eating dirt. They make it for inside or outside tortoises (the inside kind has D3 in it whereas the outside one does not contain D3). I buy mine from Petmountain.com.
I'm sorry. "Veggie" is a bit too vague. What kind?
These guys are broadleaf weed eaters. They need a diet that is hi in fiber and that has a high calcium to phosphorous ratio. Grocery store veggies tend to be weak in both areas. Sounds like you might need more weeds, leaves, flowers and succulents in the diet.
Also, what sort of lighting are you using? Infrared bulbs? Colored lights for night time? Any UV bulbs?
Mine eat rocks if there is no cuddlebone.
The issue is with impaction. Not with the composition of the rock or the sand. The rocks don't get digested and may or may not get passed normally.