Cassiterite, a heavy dark tin oxide found in and around the granite uplands of Cornwall and Devon. In the 12th century it was won mainly by streaming: digging alluvial gravels in valley bottoms and washing them in diverted water so that the heavy ore settled while lighter waste was carried away. Mining into the veins themselves was rare before the later Middle Ages. The earliest written record of tin streaming is 12th-century.
Caveats (confidence: high)
The term 'black tin' for dressed ore is used in the game; its use as early as the 12th century was not confirmed.
Sources: historyofeconomicthought.mcmaster.ca · en.wikipedia.org
Made by
- Dig ore
Used to make
- Dress tin ore to black tin by hand
- Stamp and buddle tin ore to black tin