The following items are usually found while adventuring.
Bags of Gems (smooth, polished gems, not rough cut stones)
Gem bags come in three sizes, using an average size man's fist as a measurement, a small bag is about half of one, a medium a whole one, and a large bag is two. These are basic values.
A small bag of small gems = 10 silver
A medium bag of small gems = 15 silver
A large bag of small gems = 50 silver
A small bag of large gems = 10 gold
A medium bag of large gems = 50 gold
A large bag of large gems = 100 gold
Single, smooth, polished gems usually to large to be suitably bagged, gold value.
Glitter Stone = 5 to 25, light colored stones are worth more.
Yellow Diamond = 250
Blue Diamond = 500
White Diamond = 1000
Red Diamond = 2500
Black Diamond = 5000
Teardrop Ruby, Jade, or Opal = 200
Blue Jade = 100
Dewdrop Opal = 75
Blue Water Stone = 450
Black Onyx = 325
Common Flint = 1 silver
Jewelry's worth is decided on a piece by piece basis. How common such pieces are, their craftsmanship, the metals and stones used, and what condition it is in, are all factors contributing to its worth.
Gold, silver, platinum, iron, and other unprocessed ores are weighed and assessed differently from place to place, making raw ore, or unpressed coin, a bit unpredictable when it comes to worth.
Trade goods are also assessed differently from place to place; hides, herbs, weapons, armor. equipment, etc.