by the late Piet Lamont
So we’ve found some beautiful opal. Now to cut and polish one of nature’s gems.
Firstly we remove any sandstone from the rough opal using a 220 grit diamond wheel and the word is – keep cool – make sure the opal is not overheated – use plenty of water as the coolant.
Next we rough shape the piece and glue the stone onto a wooden “dop” stick. With the stone dopped, grinding is done on the 220 wheel till the exact shape you have in mind is achieved. Turning the stone 360º reveals good symmetry all round. The stone is now worked on a series of diamond impregnated “Nova” wheels – first 360, second 400, third 600, fourth 1200 all the time ensuring lots of water is fed onto the stone to keep heat to a minimum and to carry away grinding debris.
Wow, look at the beautiful stone now – its nearly finished. A quick 3000 and if you are really serious about a mirror finish, I complete polishing on a felt pad impregnated with a high quality cerium oxide and water mixture.
Take the stone off and redop (reverse the stone) to finish the backside. All I do is flatten the back using a 220 flat lap and then finally put a setting edge on the stone.
Ah, perfection – a gem from nature with a little help from its friends.