There are all sorts of micro-probes capable of mapping out gold grains. I've made reference before to one that resides in the basement of the physics building at the University of WA that I have seen with my own eyes. The machine is called a JEOL 8530F microprobe, it is basically an advanced SEM and works with a beam of high energy electrons.
Here is a link to this machine which can produce a two dimensional elemental mineral map with a 1-µm resolution.
There are also micro-probes that work on a different principal, ie not a high energy electron beam that is fired at a polished surface to detect the scatter products.
Here is a link to s Laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS).
Sounds complicated but it isn't. Basically a high powered laser beam is focussed on a sample and melts the surface. The products given off in the plasma are then analysed.
The LA-IPC-MS micro-probe in the link below can create a gold intensity map with trace elements over an area of 550 µm x 500 µm with a 5-µm resolution in 12 minutes. The example in the link shows a detrial gold grain about
400 µm wide with trace element densities (Ag, Pd and Te).
There are many ways/machines that can be used to map fine gold grains in rock samples if visible light methods fail.
Most of my other posts on this subject have been fobbed off as mumbo jumbo by Midnight, so I'll just expect the same again. That's what he does. He just deflects arguments based on real science. Esh
