Garnier et al. (2008) proposed that

Garnier et al. (2008) proposed that this marble originated from an old carbonate platform (considered Precambrian to Permo-Triassic), which later metamorphosed. Graphite crystals in these Vietnamese marbles likely derive from metamorphism of organic matter (Giuliani et al., 2003; Garnier et al., 2008). As already mentioned, blue spinels are always associated with olivine (nearly pure forsterite).