Yes it would make a good treasure to Dowse. 20.2 Troy pounds of Gold, Rubies, Emeralds, Diamonds. Not sure how far 20 lbs of gold signals, maybe 5 miles. Montana or Wyoming ?
If I was to Dowse for Forest Finn Treasure, my primary signal Element, would be Gold, because the 20 hidden lbs., would create the furthest/longest signal line. 20 lbs Gold can signal 5 miles, when Rubies, Safires, Emeralds and Diamonds, don't have enough Element to signal as far, on their own. But, because they are combined in a box, all Elements will Ride the wave/Piggyback the Gold signal. The gem signals can be dowsed in the Gold line, just as far as the Gold.
Low grade Gems work well for signals, and sandpaper made of the Gem, can be folded into a bigger more area signal.
Confirmation of contents can be dowsed from great distance. Meteorites carry some o the same Elements in the box. Use Elements that are not in the box, to eliminate Meteorites. Use Nickel, Ytterium, Copper, Aluminum, Iron, Platinum, ect. If they all signal, it's a Meteorite, not the Finn Treasure. Dowser