“ Alchemical Gold - popular in the weapons of the nobility, this allows for gold to be used in their swords and lances without the fear of the metal bending, deforming or otherwise breaking in combat.”
“ A small, primitive village has yet to discover fire, which is a good thing because there are highly flammable (but not otherwise dangerous) gasses in the air. The heroes, blissful in their ignorance, don't know that and think it a wonderful idea to show the locals open flame.”