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

CUVOPA205A Mapping and Delivery Guide
Complete pre-cutting processes for opal doublets and triplets

Version 1.0
Issue Date: April 2024


Qualification -
Unit of Competency CUVOPA205A - Complete pre-cutting processes for opal doublets and triplets
Description This unit describes the performance outcomes, skills and knowledge required to select and prepare opal and backing materials for cutting as doublets or triplets and complete all pre-cutting processes.
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 completing pre-cutting processes for opal doublets and triplets.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: Select opal for cutting as an opal doublet or triplet
  • Select suitable materials for cutting as a doublet or triplet based on market requirements and characteristics of the stone
  • Determine best play of colour and mark that side
  • Check for flaws with powerful light source and correct if necessary
  • Follow general OHS principles and safe operating procedures when using machinery for opal cutting
       
Element: Flatten opal and base
  • Flatten opal on marked side until surface is free of potch and impurities and is completely down to the colour bar using appropriate equipment
  • Select backing materials and flatten
  • Lap opal and base until flat satin finish is obtained
  • Clean and dry opal and base
       
Element: Cement components together
  • Blacken flattened surface with appropriate blacking agent
  • Mix adhesive in line with manufacturers’ instructions
  • Ensure stone is cemented with the best colour face down
  • Cement flattened surfaces together eliminating excess adhesive and air bubbles
  • Allow adhesive to harden following manufacturers’ instructions
       
Element: Pre-form opal doublet
  • Grind stone to expose join between opal and backing
  • Grind stone to expose best colour
  • Grind to rough shape
       
Element: Convert doublet to triplet
  • Manufacture a triplet working with a very thin opal layer
  • Lap the colour surface of the opal until a thin layer of opal remains on the backing
  • Clean and dry stone
  • Cement manufactured triplet top or preferred alternative to the opal surface, eliminating excess adhesive and air bubbles
  • After curing, grind the stone to expose both joins
       


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:

select appropriate materials for making opal doublets and triplets

complete pre-cutting processes using safe work practices.

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 and other methods as required

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 select and prepare opal backing materials for cutting

problem-solving skills to identify and address common problems associated with pre-cutting processes

numeracy skills to use numerical features of machinery

technical skills to:

complete pre-cutting processes for opal doublets and triplets using correct technique and equipment

work safely with opal-cutting equipment and materials.

Required knowledge

characteristics of opal gemstone structure

processes, materials and consumables needed for making doublets and triplets

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.

Suitable materials may include:

multiple bars of colour with potch between

off-cuts from solid production

opal from unsuitable boulder iron stone

opal prone to crack (triplet only)

opalised shell skins

thin bar of colour in potch

thin seam opal

weak colour on a clear base (jelly opal).

General OHS principles and safe operating procedures may include:

complying with the safe operating procedures for each machine

good housekeeping

using personal protective equipment (PPE) where required.

Appropriate equipment may include:

diamond grinder

diamond saw

free-hand saw

silicon carbide grinder

slab saw

trim saw.

Backing materials may include:

black jade

black potch

boulder iron stone

clear or transparent potch

dark grey potch

glass (triplet only)

obsidian (black)

vitrolite (triplet only).

Blacking agent may include:

black epoxy additives

black permanent markers

nigrosine.

Adhesive may include:

Loctite UV 358 or 363 (triplet top to opal)

UHU Plus 24hr (opal to backing)

other glues, such as:

UHU Quickset

Megapoxy 69

Epoxy 330

Tenax+ super glue

Bond 527

Tite On.

Triplet top may include:

clear quartz

commercial standards size triplet tops

glass, plain or plate

lead crystal glass

synthetic spinel, corundum and topaz.

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
Select suitable materials for cutting as a doublet or triplet based on market requirements and characteristics of the stone 
Determine best play of colour and mark that side 
Check for flaws with powerful light source and correct if necessary 
Follow general OHS principles and safe operating procedures when using machinery for opal cutting 
Flatten opal on marked side until surface is free of potch and impurities and is completely down to the colour bar using appropriate equipment 
Select backing materials and flatten 
Lap opal and base until flat satin finish is obtained 
Clean and dry opal and base 
Blacken flattened surface with appropriate blacking agent 
Mix adhesive in line with manufacturers’ instructions 
Ensure stone is cemented with the best colour face down 
Cement flattened surfaces together eliminating excess adhesive and air bubbles 
Allow adhesive to harden following manufacturers’ instructions 
Grind stone to expose join between opal and backing 
Grind stone to expose best colour 
Grind to rough shape 
Manufacture a triplet working with a very thin opal layer 
Lap the colour surface of the opal until a thin layer of opal remains on the backing 
Clean and dry stone 
Cement manufactured triplet top or preferred alternative to the opal surface, eliminating excess adhesive and air bubbles 
After curing, grind the stone to expose both joins 

Forms

Assessment Cover Sheet

CUVOPA205A - Complete pre-cutting processes for opal doublets and triplets
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

CUVOPA205A - Complete pre-cutting processes for opal doublets and triplets

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: