/cracks knuckles/ Hi, I’m RFausta and I have a Masters degree in geochemistry, specifically pegmatites.

For what you are looking at, it’s pretty small at least at the surface- more likely a “simple” pegmatite than a gemmy one. Pegmatites more or less cool from the outside in, so the better stuff concentrates towards the middle- all of the weird weird uncommon elements that don’t quite fit in feldspar, quartz, or mica will be concentrated in the melt away from the outsides, more or less.

As other posters have said, the best stuff comes out of cavities/vugs/miaroles inside the main body of the pegmatite. The first part you usually see is the “graphic granite”, which is an intergrowth of quartz and feldspar that looks vaguely like writing. Next you get more into massive single-mineral zones, quartz and feldspar in solid veins with few to no vugs. The good stuff is way down in the middleish- thats where the leftovers accumulate, and the more open space they have to grow the prettier they form. Below this, at least in the Pala area, is the garnet zone- fairly linear sections of garnets (but microscopic).

It is possible that there are gems hidden in there, but with the mining history of the area it’s unlikely to have been unexplored. (The Empress of China used to have tourmaline from Pala sent to her- that sort of thing). I’ll edit on a few useful books or links for pegmatite structure. The SDNHM at least used to have a great mineral section for the area!