Polishing Clear Opals: Achieving Brilliance & Play-of-Color

Question
I have clear opals that I am trying to polish (rotary tumbler), but they aren't polishing, and there's very little "fire" to them. What do I need to do to get them to show Fire, and to clear up? They were clearer before I started them than they are now, after two full cycles in the tumbler.

Answer
Hi Mary Lou , well ..firstly  what type of opal is it ? from where is it light  or boulder or sandstone ? is there sand  or other host rock ? Fire:  The fire has to be there before hand polishing would make the stone clearer but if there's no fire to begin with there wont be any fire after . Tumbling requires several steps with opal , beginning with silicon carbide  coarse , the last two steps are fine pumice  and the last is cerium oxide (red ).It depends what state the rough is in before you polish it.two full cycles in the tumbler is not enough. Hope that helps , remember the first step needs  to shape the stones , next takes out scratches , third is polish. best regards Rod Keady  www.keadyopals.com