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 separation (ex:W10,W5,K5…).