This item was in game when the wizard spell Imbue: Fire Opal was added (kunark). I remember because I had them in original Velious. They are on p99 because obviously. It appears that developers for the TLPs thought that the stats seemed to powerful and delayed them until Luclin?
Back in the day every wizard took sol ro to wear these rings - there was no imbalance - only wizards can wear them lol. You could give wizards a +1000 intelligence ring and it wouldnt balance wizards in velious.