Sekkachi Hakushaku to Jikan Dorobou - Vol. 1 Ch. 5 - The Count That Laid The Golden Eggs

[MangaDex]

 

[Beregorn]

9k gold is paid around 20$ per gram... Definitely not worthless.
If you consider that extracting gold from rocks at a rate of 1-2g per tonne is a really profitable business, anything containing a measurable concentration of gold is worth buying.