[ravenfish]

For objects with value only from cultural significance and not from materials, it makes sense that they're basically worthless if the cultural significance isn't recognized. A rare postage stamp could be worth millions to collectors but would fetch only a tiny fraction of a penny to someone trying to sell it for scrap paper.


[From a game point of view, it might seem unsporting to gate significant treasure value behind a single roll to recognize the treasure, but, in genre, there's a tradition of valuable hidden loot that is effectively gated behind a roll to find it, so it's not without precedent. Plus, if the players are worried, they can always hire an agent back in town to go through their scrap and see if they've missed anything valuable.]

EDIT: For some of the examples beaushinkle gave, I would rule as a GM that Giant Spider Silk Light Armor, on a failed roll, would be mistaken for ordinary cloth armor rather than worthless junk, and jewelry is almost always obvious as jewelry (and therefore probably worth taking to an appraiser) even if the character has no idea of its actual value.