Bold Artifacts are special items that your hero may come across while questing. Your hero will not find these types of artifacts very often as they are quite rare, but as such, they fetch a higher price then normal artifacts at the merchant.
List of Bold Artifacts
How to recognise
The names of these artifacts appear Bold.
How to use
The god can urge the hero to use any bold artifact in precisely the same way as any other artifact; although there always is a chance the hero will lose (destroy, etc.) the artifact in question, so it doesn't make any sense to lose a bold (expensive) one when there are cheaper alternatives.
It is worth noting that a few Bold Artifacts have special uses.