When digging Clay in shallow water, there's the chance to find occasional Gold Pebbles. (https://ringofbrodgar.com/wiki/Gold_Pebbles)
How about being able to use Rustroot Extract to prospect rivers/ lakes/ bodies of shallow water, and identify potentially good places for gold panning (sifting the sand/soil looking for tiny pieces of gold)?
Panning for gold could be a way to produce some basic resources, possibly Sand, and have a small but still better chance of obtaining Gold Pebbles. It could also be less energy-demanding than digging Clay.