Unit of Competency Mapping – Information for Teachers/Assessors – Information for Learners

CUVOPA204A Mapping and Delivery Guide
Cut and polish solid opals

Version 1.0
Issue Date: April 2024


Qualification -
Unit of Competency CUVOPA204A - Cut and polish solid opals
Description This unit describes the performance outcomes, skills and knowledge required to cut and polish a solid opal to make a finished cabochon or other shape from a pre-formed stone.
Employability Skills This unit contains employability skills.
Learning Outcomes and Application The skills and knowledge covered by this unit are applied in a workshop environment and include all phases of the process for cutting a variety of opal shapes to accepted industry standards and using equipment safely.Where appropriate the outcomes of this unit could be contextualised to apply to other gemstones.
Duration and Setting X weeks, nominally xx hours, delivered in a classroom/online/blended learning setting.
Prerequisites/co-requisites Not applicable.
Competency Field
Development and validation strategy and guide for assessors and learners Student Learning Resources Handouts
Activities 		Slides
PPT 		Assessment 1 Assessment 2 Assessment 3 Assessment 4
Elements of Competency Performance Criteria              
Element: Prepare to cut an opal solid
  • Identify and obtain consumables required for cutting an opal solid
  • Select tools and equipment to be used
  • Determine jewellers’ cuttingangle requirements
  • Dop pre-form on appropriate dop stick using wax or adhesive as appropriate
  • Follow general OHS principles and safe operating procedures when using tools, equipment, machinery and consumables for opal cutting
       
Element: Cut and polish top surface of opal
  • Fine grind shape and dome ensuring continuity of contour and maintaining jewellers’ setting angles
  • Sand opal to remove grinding marks using appropriate sanding papers or diamond wheel
  • Polish top surface of opal with polishing compound to a high lustre
       
Element: Cut and polish back surface of opal
  • Remove stone from dop, turn over and replace on dop checking alignment
  • Grind the back of the stone to jewellers’ standards maintaining continuity of form and alignment
  • Sand to remove grinding marks and polish if required
  • Remove the stone from the dop and clean the stone
       
Element: Treat opal specimen
  • Select opal specimen for treatment and check to ensure it will benefit from treatment
  • Grind, sand and polish selected area
  • Treat the selected area
  • Clean or neutralise as required
       


Evidence Required

List the assessment methods to be used and the context and resources required for assessment. Copy and paste the relevant sections from the evidence guide below and then re-write these in plain English.

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.

Overview of assessment

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

Evidence of the ability to:

apply knowledge of the processes for cutting and polishing opals in a range of shapes

achieve a high quality finish that satisfies the requirements of the jewellery industry.

Context of and specific resources for assessment

Assessment must ensure access to an opal-cutting workshop with stones and equipment.

Method of assessment

A range of assessment methods should be used to assess practical skills and knowledge. The following examples are appropriate for this unit:

observation of processes and procedures

oral and/or written questioning on underpinning knowledge and skills

evaluation of the final product

review of portfolios of evidence

review of third-party workplace reports of on-the-job performance by candidate.

Assessment methods should closely reflect workplace demands (e.g. literacy) and the needs of particular groups (e.g. 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).

Guidance information for assessment

Holistic assessment with other units relevant to the industry sector workplace and job role is recommended.

Submission Requirements

List each assessment task's title, type (eg project, observation/demonstration, essay, assignment, checklist) and due date here

Assessment task 1: [title]      Due date:

(add new lines for each of the assessment tasks)

Assessment Tasks

Copy and paste from the following data to produce each assessment task. Write these in plain English and spell out how, when and where the task is to be carried out, under what conditions, and what resources are needed. Include guidelines about how well the candidate has to perform a task for it to be judged satisfactory.

Required skills

planning and organising skills to plan work logically

problem-solving skills to identify and address common cutting and polishing problems

numeracy skills to use numerical features of machinery

technical skills to cut and polish opals using correct technique.

Required knowledge

characteristics of opal gemstone structure

processes and consumables needed for cutting and polishing opals

safety issues associated with opal cutting and polishing machinery.

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.

Consumables may include:

cerium or tin oxide

cleaning spirit

diamond or silicon carbide wheels #220 or #360

diamond polishing compound #2400 to #100000

diamond polishing wheels #3000 to #50000

diamond sanding wheels #280 to #1200

felt or leather buffs

silicon carbide sanding paper #180 to #600

wax or adhesives for dopping.

Equipment may involve:

appropriate ventilation

grinding machinery

personal protective equipment (PPE)

polishing machinery

sanding machinery

saws.

Jewellers’ cutting angle requirements may include:

10º to 12º side angle (from setting edge to start of dome)

35º to 45º back setting edge (standard solid)

all sharp edges or acute angles to be slightly rounded

flat or domed back

high overall polish and free of defects

proportions of low, medium and high domes to be maintained

sanded or polished back

setting edge to be straight and parallel to back

thickness of stone not to exceed 2/3 of width (standard solid)

tolerance for standard millimetre sizes, 0.2mil. + or −

when leaving potch or boulder on back of stone, maintain proportions in relation to stone size, i.e. approx. 2/3 of width.

General OHS principles and safe operating procedures may include:

complying with the safe operating procedures for each machine or process

good housekeeping

using PPE where required.

Shape and dome may include:

a variety of other shapes

cabochon

dome – high, medium and low

free form

rectangles

shapes.

Treatment may include:

sugar and acid treatment

sugar and heat treatment.

Copy and paste from the following performance criteria to create an observation checklist for each task. When you have finished writing your assessment tool every one of these must have been addressed, preferably several times in a variety of contexts. To ensure this occurs download the assessment matrix for the unit; enter each assessment task as a column header and place check marks against each performance criteria that task addresses.

Observation Checklist

Tasks to be observed according to workplace/college/TAFE policy and procedures, relevant legislation and Codes of Practice Yes No Comments/feedback
Identify and obtain consumables required for cutting an opal solid 
Select tools and equipment to be used 
Determine jewellers’ cuttingangle requirements 
Dop pre-form on appropriate dop stick using wax or adhesive as appropriate 
Follow general OHS principles and safe operating procedures when using tools, equipment, machinery and consumables for opal cutting 
Fine grind shape and dome ensuring continuity of contour and maintaining jewellers’ setting angles 
Sand opal to remove grinding marks using appropriate sanding papers or diamond wheel 
Polish top surface of opal with polishing compound to a high lustre 
Remove stone from dop, turn over and replace on dop checking alignment 
Grind the back of the stone to jewellers’ standards maintaining continuity of form and alignment 
Sand to remove grinding marks and polish if required 
Remove the stone from the dop and clean the stone 
Select opal specimen for treatment and check to ensure it will benefit from treatment 
Grind, sand and polish selected area 
Treat the selected area 
Clean or neutralise as required 

Forms

Assessment Cover Sheet

CUVOPA204A - Cut and polish solid opals
Assessment task 1: [title]

Student name:

Student ID:

I declare that the assessment tasks submitted for this unit are my own work.

Student signature:

Result: Competent Not yet competent

Feedback to student

 

 

 

 

 

 

 

 

Assessor name:

Signature:

Date:

Assessment Record Sheet

CUVOPA204A - Cut and polish solid opals

Student name:

Student ID:

Assessment task 1: [title] Result: Competent Not yet competent

(add lines for each task)

Feedback to student:

 

 

 

 

 

 

 

 

Overall assessment result: Competent Not yet competent

Assessor name:

Signature:

Date:

Student signature:

Date: