A gold and silver deposit formed at shallow depth by hot fluids, typically high-grade and structurally controlled.
A mineral deposit formed at shallow depths and low temperatures from hydrothermal fluids. Epithermal deposits are important sources of gold and silver and are classified as low-sulfidation or high-sulfidation based on their geochemistry.
Epithermal systems produce the spectacular drill intercepts juniors are re-rated on. They are also narrow and erratic, so tonnage is usually the constraint rather than grade.
Look for the vertical extent of the system and evidence it stays mineralised at depth. Many epithermal deposits are rich near surface and pinch out quickly.