Google Links

Follow the links below to find material targeted to the unit's elements, performance criteria, required skills and knowledge

Elements and Performance Criteria

  1. Set up faceting equipment.
  2. elect, pre-shape and dop selected opal piece.
  3. Grind, sand and polish pavilion.
  4. Transfer stone.
  5. Grind, pre-polish and polish crown.

Evidence Required

The evidence guide provides advice on assessment and must be read in conjunction with the performance criteria required skills and knowledge range statement and the Assessment Guidelines for the Training Package

Critical aspects for assessment and evidence required to demonstrate competency in this unit

To achieve competency in this unit a person must be able to produce a faceted opal that satisfies industry standards

The assessment must confirm the ability to select opal pieces suitable for faceting and use faceting equipment to produce and polish a faceted opal that conforms to industry standards All work must be done following OHS requirements for machinery and equipment procedures

Competence in this unit must be assessed over a period of time in order to ensure consistency of performance over the range of variables and contexts applicable to the work environment

Context of and specific resources for assessment

This unit may be assessed in a work environment in a simulated work environment or in a combination of these situations

Method of assessment

For valid and reliable assessment of this unit evidence should be gathered through a range of methods to indicate consistent performance

Assessment of this unit of competence will usually include observation of processes and procedures oral andor written questioning on underpinning knowledge and skills evaluation of the final product and other methods as required

Assessment methods should closely reflect workplace demands eg literacy and the needs of particular groups eg people with disabilities and people who may have literacy or numeracy difficulties such as speakers of languages other than English remote communities and those with interrupted schooling

Assessment of this competency requires access to

a faceting machine and appropriate consumables

a qualified workplace assessor or assessment team


Range Statement

The range statement relates to the unit of competency as a whole. It allows for different work environments and situations that may affect performance. Bold italicised wording, if used in the performance criteria, is detailed below. Essential operating conditions that may be present with training and assessment (depending on the work situation needs of the candidate, accessibility of the item, and local industry and regional contexts) may also be included.

Faceting machines may include:

FACETRON (USA)

GEMMASTA (Aus)

GRAVES (USA)

Jamb-peg

Platform

POLY-METRICS (USA)

Post

RAYTECH (USA)

ULTRA TEC (USA).

Faceting machine components and laps may include:

components:

angle vernier (protractor)

coolant tank

forward/reverse switch

handpiece (quill)

height adjuster, coarse and fine

index wheel

master lap

radial vernier (cheater)

sliding post

variable speed control

laps:

angle vernier (protractor)

coolant tank

forward/reverse swit

handpiece (quill)

height adjuster, coarse and fine

index wheel

master lap

radial vernier (cheater)

sliding post

variable speed control.

Faceting laps diamond grit size may include:

coarse #80, #100, #120, #180

fine #800, #1000, #1200

medium #220, #320, #360, #400, #600

polish #14000, #50000, #10000

pre-polish #2400, #3000, #8000.

Maintenance checklist may include:

check electrics regularly for faults and water seepage

cover machine when not in use

keep all laps separate from each other

keep whole machine clean

oil and clean moving parts

read manufacturers manual and keep near machine.

Opal suitable for faceting may include:

Aus. Clear jelly opal

Aus. Electric blue opal

contra-luz

Mexican cherry opal

Mexican fire opal

any transparent opal.

Angles may include:

critical angle 43½º

crown main 43º

culet angle 44º

girdle breaks, main angle plus 6º to 15º

pavilion main 45º

star facets, main angle minus 15º

table facet 0º.