Your 1952-D quarter has a type 1 obverse. (thick middle cross bar of LIBERTY, type 2 has thin middle cross bar) The D mint mark appears to be a medium to me. The small D has thin pointy serifs, the medium has a large rounded serif at the top and a small serif at the bottom, and the large D has large rounded serifs top and bottom. I t is hard to tell exactly because the mint mark has some damage.