Nebula X by Vargo Statten

"Nebula X" by Vargo Statten, published 1950, opens in a futuristic atomic laboratory where young scientist Lance Barclay operates massive transmutation equipment for Transmutations Limited, converting base metals into valuable substances using extreme electrical energy. In the year 1970, Lance converts pig-iron into beryllium in a vacuum tube. Upon opening the tube, Lance and colleague physicist Jeffrey Walcott discover a mysterious unconscious woman inside—impossible given the tube's lethal conditions. The woman, whom they name Nebula, awakens speaking an incomprehensible melodious language and exhibits exotic features: olive skin, a golden abbreviated swimsuit, and most remarkably, eyes that change color from crimson to sapphire to brown as witnesses observe them. When laboratory curator Dr. Masters interrupts and views her, he reports her eyes as brown. The story establishes Nebula as an entirely unknown type of being, possibly extraterrestrial, whose very presence defies scientific explanation.