Score plot and projection of the variables on PC1 and PC2. Variables: 21
fitting parameters of the Raman CH band. Items: 10 archeological copals, surface
sampling. The samples are separated in 2 groups among the PC1: the altered and
red copals on one side, the dry and yellow copals and the other side. The variables
projection shows what parameters have an important contribution to this separa-
tion (ex:W10,W5,K5…).