Yes, it is the same thing you give birds, in fact that is where you will find it at the pet store, in the bird section. It does have one side that has a hard backing on it that most people recommend you remove (chip it off with a sharp knife). Then you can toss the whole thing in the tank or break it into smaller pieces and toss them in as needed. Your turtle might ignore it at first but eventually might take a bite out of it. I leave one in my tank all the time and it just gets smaller and smaller until one day it is gone. It is very inexpensive and a great source of calcium for your turtle.
Nancy