Figure 3 : Pearson’s correlation coefficients between each element for Asian and African elephant tusks combined, as determined by XRF analysis.

From: Use of handheld X-ray fluorescence as a non-invasive method to distinguish between Asian and African elephant tusks

Figure 3

Colored boxes indicate direction and strength of each correlation. (Mg = magnesium, Al = aluminum, Si = silicon, P = phosphorous, S = sulfur, Cl = chlorine, K = potassium, Ca = calcium, Ti = titanium, V = vanadium, Cr = chromium, Mn = manganese, Fe = iron, Co = cobalt, Ni = nickel, Cu = copper, Zn = zinc, Zr = zirconium, Mo = molybdenum, Ag = silver, Cd = cadmium, Sn = tin, Sb = antimony, W = tungsten, Pb = lead).