The blue-green eggs of a 70-million-year-old oviraptor called Heyuannia huangi.
H. Huangi was among 15 Cretaceous-era dinosaurs and extinct birds represented in a stash of ancient eggshell fragments analyzed in that 2017 study.
Using Raman microspectroscopy, scientists bounced lasers off the shell fragments’ surfaces to see what it revealed about their molecular makeup.