Feeding and Nutrition :: Calcium from shells?

[Outlander]

So because I'm a westcoaster, I've decorated the bottom of my turtle's tank with several (well cleaned) seashells and sand dollars. Today when cleaning I noticed one of the sand dollars had a hole in it. When I put it back in the tank my turtle started biting it, breaking pieces of it off. Should I take it away? Or let him continue to eat it as a source of calcium? The skeleton of a sand dollar is made of magnesian calcite (magnesium plus calcium carbonate) so I can't really see it as being harmful, especially since snail shells are made of calcium carbonate and turtles eat them with no problem! What do you guys think?

[SINI5T3R]

I think it would be good for them, should be just like cuttle bone if you ask me.

[worldpeace]

You shouldn't worry. They're 100% calcium, exactly like a cuttlebone just maybe a little harder. If your turtle is eating it, let him do it.

[Outlander]

Yeah, I just let him. Looking into it it's not that different from eggshells or any other shell material.