You are correct sir!.. not possible to do whole rock analysis accurately… multimineralic rocks which include lapis lazuli do not provide accurate reading since each mineral has a different composition. individual mineral grains have to be picked out, crushed and scanned. As and other heavy metals can confound each other… Lanthanides in particular are difficult as they require high exitation energies and have similar electronic structures…people who use them to find gold will not be satisfied and the sensitivity for gold is low… has to be 100 ppm range… still sensitive to detect it but not quantitatively accurate. It’s a good screening tool… electron microprobe analysis is far better suited for individual mineral grain analysis…however the cost of a machine is between 0.5 to 1.5 million dollars. run times charges are 50 to 150 dollars per hour for academic machines that do analysis for the public and industry…It cannot distinguish between isotopes… Still a lot cheaper than 2K or more per sample for laser ablation induction coupled plasma mass spectrometry. This is far beyond my budget… I could use the money for international travel instead.
