Nugget

Nugget is a Goldfox. These foxes are Naturally more sensitive to the presence of gold, which is why they're being sought after much by Treasure hunters.
Nugget and Hazel have had a strong bond from a young age.

The gold sensitive antennae release some fluid that can be consumed by another creature, that will then temporarily be instilled with the goldradar ability that the goldfoxes have. The fluid is dangerous to ingest in its pure form, and has to be treated before you can safely ingest it. Just like goldfoxes, It's highly sought after and has a high marketvalue. Hazel is years in the process of making this potion better and better. She's still finding the best way to distill goldfinders potion.