At the end of the day, if someone gives you X for Y, then at that point, to you both, one values X at Y, and one values Y at X.
I personally wouldnt give you anything for diamonds or shards. But that doesnt mean its worthless, and doesnt mean someone else would.
If you want to start setting values, put your money where your mouth is, start offering coin for said items
Will you give me gold for the shards and the diamonds Fang?