And make for nice props that show up well on a 90s CRT, and they fit the Stargate aesthetic that lifted many 60s hippy occultist ideas including both "pyramids are too advanced, space aliens must have built them"[0] and "crystal skull has psychic powers"[1].

[0] https://en.wikipedia.org/wiki/Chariots_of_the_Gods%3F (hmm, even the book name sounds like two SG-1 episode titles, pilot and when thrmey meet Thor)

[1] https://en.wikipedia.org/wiki/Crystal_skull