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