Jewelry, Gems, & Minerals/Andamooka opal


hello, I have a nice sized unfinished andamooka opal, I have it ground to the shape and size I want. yes I used a dremel and I know I shouldn't have but its all I have at this point, and it turned out perfectly.  I know it needs to be sanded now, im not sure what to use as I have to do it by hand. and more importantly I need to know what to finish it with.  epoxy or laquor seem to be my choices, im leaning to liquor as it comes in spray cans.  help please.  shawn

Hi Shawn ,

Cool !!! ... Andamoooka is one of my favourites ...
butt he big question is ...Is it Opal or Matrix Opal ? without seeing it  I can only offer the following

If its solid Opal ...definatley polish it as you would any other opal surface

grind  > dop it up ( on a stick ) > shape on wheel  > sand  with  400 + 600 papers  dry  ( careful not to overheat or burn surface )  then wet Pumice wheel  then wet Cerium oxide  or  Tin Oxide  slurry on leather wheel .Result = mirror glass finish !

I would never use lacquer or epoxy  firstly it would never look as good as polishing the surface itself and secondly ...if it is going touch someone's skin in a pendant or a setting to be worn on a persons' body could react with their skin and give a nasty reaction..(old treated matrix with sugar and acid was the first of alarm bells for stones people wear on skin , especially woman.
Woman often wear lots of perfume and the chemicals can react there are a handful of other reasons I wont go into now ...

If its Andamooka Matrix, well... that is a bit more tricky, as there are mixed surfaces there and you would need various courses of diamond pastes on a hard felt wheel ( usually a dremel )to prevent undercutting of one of the surfaces ...

I hope that helps ... it is very rare to produce anything much these days from Andamooka ...the blue green and orange crystal must be one of the most beautiful gems on earth ....if you can find them .
good luck  

Jewelry, Gems, & Minerals

All Answers

Answers by Expert:

Ask Experts


Rod Keady


all info pertaining to australian opals and opal fields is ok. online valuations is difficult but not entirely impossible. Photographs of stones should clearly show weight in carats and scale in mm. naturally photographs of opals are the hardest thing to take as a slight shift in direction displays a new colour or plane


Born into a pioneering opal family , now 48 yrs old , visited every opal field in australia, seen some of the finest stones ever produced . Sold high quality gems to japanese collectors and europeans and Americans
Have an incredible photogallery of opals ...try me !

The Directory of Australian Opal Dealers AGIOA Basel Gem Fair
Iwaki Dinosaur Fair Ibaragi Prefecture Japan
International Jewelry Tokyo .
Hong Kong Jewellery Show , Bankok Jewellery Show, Hiroshima Exhibition of Fine Gems, Tokyo International Jewellery Fair . various gem and jewellery WEBSITES

Sydney Grammar School graduate

©2017 All rights reserved.