Elements and Performance Criteria
- Prepare to cut an opal doublet or triplet
- Cut and polish an opal doublet or triplet
- 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