Gold does not always distribute evenly. In coarse-gold or 'nuggety' systems, gold occurs as discrete particles, so a single half-metre sample can hit a cluster of grains and assay at hundreds or thousands of grams per tonne, while the sample beside it returns almost nothing. That is the nugget effect, and it is why a headline like '1,604 g/t over 1 metre' can be simultaneously true and nearly meaningless as a guide to the deposit.
The defence is context. A spectacular assay means something if it sits inside a broader mineralised interval — say, that same metre within five metres of several-hundred-gram gold — because then the spike is hosted in continuous vein, not floating alone. A four-figure grade reported over a single isolated interval, with barren rock on either side, tells you the system exists but not that it is economic.
Statistically, nuggety deposits are also the hardest to estimate, because a few high samples can dominate an average. When you see an enormous grade over a short width, do not celebrate the number — go looking for what surrounds it.