While looking arround my bank for items to use for gaining EP, I found my ring of stone protecting over almost everything. I thought this was odd since I was sure tip.it's item DB had very low alchemy values. So I checked what a general store would buy them for:

 

 

 

 

The item database says it only low alchs for 3334gp.

 

http://www.tip.it/runescape/index.php?rs2item_id=4308

 

 

 

I checked the item DB for onyx through all of its forms (excluding bolts) and they all seem correct except for the ring of stone, which high alchs for 121,200gp and low alchs for 80,800gp, and possibly the unstrung onyx amulet which it says alchs for 0gp. However I don't want to buy an unstring onyx amulet just to test that, I'll leave that for someone on the crew.

Thanks! Updated and credited!