These are not assay results, these results are from a LIBS unit....

These are not assay results, these results are from a LIBS unit. A LIBS unit uses a concentrated laser beam to create plasma around the area stuck, stripping atoms from the material. As this plasma cools, atoms recombine with electrons and in the process emit light in the UV, optical and IR regimes which is detected by the unit to give a reading.

The key thing to note is that this is a point sample taken over an extremely small area and not a representative sample, i.e., it is likely that high Li result was directly taken on a Li bearing crystal with the pegmatite and does not (very likely given the extremely high Li% reading) include any other potentially non-Li bearing material within the sample.

Traditional assaying uses a homogenous sample derived from the crushed material of the whole sample, including Li bearing and gangue material.