Use 'lode' when discussing mining, especially when referring to rich concentrations of minerals. The miners were exhilarated to find a lode of diamonds deep underground.
Pro Tip 2/3
Value Emphasis
'Lode' implies high value, like a vein of precious metal, not just any mineral. The early settlers were drawn by tales of a lucrative gold lode.
Pro Tip 3/3
Geological Setting
Use 'lode' in geological contexts to talk about where materials come from. Geologists mapped the area to find the lode responsible for the gold nuggets found in the river.