The Shikara Stones of DOOM were alright, as a "McGuffin," in relation to the almost devil-worshipping cult surrounding it. As I understand it, they really did exist around this time, though not as Hollywoodified as we see here - obviously.
Well if nothing else, the Sankara Stones at least looked like real objects or artifacts that you might find in a museum somewhere. Which made the idea of them being at one time imbued with magical power much easier to accept.
Unlike the Crystal Skull which not only looked like something a Hollywood prop guy designed and built, but which looked way too modern for something supposedly inspired by 50s scifi.
And people talk a lot about all the ridiculous things in Doom, but for me the voodoo, dark mysticism, and evil religious cult stuff is still much more consistent with the style and spirit of the movie serials that originally inspired Indy, than the scifi stuff that happens in Skull.