Opalised Wood

I accidentally deleted my original Blip and rather than write everything out again, this is a silver ring I made a few years ago for a friend, incorporating a lovely piece of Opalised wood. I was trying to amend a reply to a comment about Opalised Wood and explain what it is when I deleted the entry. Opal is crystallised Silica, the areas where it is found used to be sea, when the sea receded, the Silica filled cracks in the rock and solidified into seams. I can only assume there were trees present when this piece was formed - it is rare and very expensive. The colour is caused by light interference in the crystals, much like a rainbow.