US 9,480,991 B2, radiofrequency particle separator.
No mesh, no filter, no chemical reagent. A radiofrequency field is aimed into a fluid carrying mixed mineral grains, and the one thing that decides which grains heat up is where the field's skin depth lands, the shell near a particle's surface the field can actually reach.
Higher frequency means a shallower shell, lower frequency reaches deeper. Tune the field so that shell lands at roughly a tenth of one particle size, and energy concentrates right where it counts instead of spreading through the whole grain, so that size heats efficiently while everything of a different size mostly does not.
Once a targeted grain gets hot enough, the fluid touching it flashes to vapor. That bubble is less dense than the fluid around it, so it floats, and the grain rides it up to a skimmer waiting at the surface. Cooler, wrong sized grains never get their own bubble and stay behind. The patent also describes a second method for conductive particles, using the field to induce an electromagnetic force directly, but the bubble lift is the one the game shows.
The one real relationship: skin depth falling with the square root of frequency, so a bigger grain always wants a lower frequency and a finer one always wants a higher one. Every number on the dial and in the assay table, gold's 18 MHz, platinum's 152, comes off that same formula, never a second, independent number.
The constant tying frequency to grain size is invented for the game. The real number depends on the fluid and the mineral's own conductivity, which the patent works out in far more depth than five bands on a dial ever could. The patent also describes an automated system sweeping frequency according to a set pattern, hands off, the same way the lumen device treats on its own once it senses something. The game puts a person on that dial instead, tracking a feed that keeps switching under them, because that is the part worth playing.
US 9,480,991 B2 · Baym, Briggs, Gilbert, Hillis, Hyde, Ishikawa, Kare, Myhrvold, Myhrvold, Pan, Tegreene, Whitmer, Wood, Wood · Elwha LLC, granted 1 November 2016.