How much metal is in the rock, in grams per tonne — the number every drill release leads with.
The concentration of a valuable mineral within ore, typically expressed in grams per tonne (g/t) for precious metals like gold and silver. Higher grades indicate richer ore deposits and generally better economics. For example, 5 g/t gold means 5 grams of gold per tonne of ore.
Grade drives everything downstream: how much rock you must move per ounce, what processing route works, and whether the deposit survives a weak price. Higher grade forgives a great deal of bad luck elsewhere.
Judge grade against the deposit type, never in isolation. Around 1 g/t gold can be economic in a bulk-tonnage open pit and hopeless underground, while 5 g/t underground is often excellent. Base metals are quoted as a percentage instead.
Comparing grades across companies without checking cut-off grades and deposit styles. It is the most common apples-to-oranges error in the sector.
108 terms have their own page: the definition, why it matters to an investor, where it shows up in practice, and the mistake people make with it.