Elements and Performance Criteria
- Prepare to cut an opal doublet.
- Cut and polish an opal doublet.
- Grind to relevant shape using colour pattern and play as a guide.
- Grind to shape incorporating jewellers side angles, including backing into shape.
- Dome the top of doublet, leaving a minimum of 1mm above join at side angle.
- Sand and polish top and sides of opal doublet.
- Turn stone over and re-dop.
- Grind, sand and polish backing at jewellers angles.
- Remove stone from dop and clean.
- Cut and polish an opal triplet (commercial top).
- Cut and polish an opal triplet (non commercial top).
- Dop pre-form with glass/quartz on top.
- Shape stone like high domed doublet on grinder.
- Transform opal colour optically into whole of dome.
- Sand and polish top and sides of stone.
- Turn stone over and re-dop on top surface.
- Grind backing thickness to 1mm.
- Grind setting edge angle at 30º, until 1mm into top, under- cutting backing.
- Sand and polish bottom and setting edge and remove any chipping that may occur around edge of top.
- Remove stone from dop and clean.
- Follow OHS principles when operating opal cutting and polishing equipment.