“On his second voyage, Frobisher found what he thought was gold ore and carried 200 tons of it home on three ships, where initial assaying determined it to be worth a profit of £5.20 per ton. Encouraged, Frobisher returned to Canada with an even larger fleet and dug several mines around Frobisher Bay. He carried 1,350 tons of the ore back to England, where, after years of smelting, it was realized that the ore was a worthless rock…”
https://en.m.wikipedia.org/wiki/Martin_Frobisher
Reading the Wikipedia article leaves one with the impression that none of the “ore” that Frobisher recovered was of any great value. The £5/4/0d per ton profit mentioned above would only, according to the
National Archives currency converter, have bought one horse in 1570.
maximus otter