Jewellery Foundations: Read Product Specifications

JTR Education · Jewellery Foundations · Module 2

A product photograph shows appearance. A useful specification explains what you are buying. This module teaches a repeatable method for reading dimensions, quantities, materials and compatibility before choosing jewellery supplies.

Suggested study: 35–50 minutes. Begin with Module 1: Observe and Describe. You need a notebook and two product listings to compare; no purchase is required.

Learning outcomes

  • Distinguish product quantity from dimensions and pack price.
  • Identify which feature a measurement describes.
  • Separate a material description from its finish.
  • Write a useful question when a specification is incomplete.
  • Compare products against a defined task.

Lesson 1 — Define the job before the product

Write down the task before browsing. What must the component do? What does it need to connect to? Which measurements or material choices constrain the result? “I need a small ring” is less useful than “I need a connecting component that passes through this opening and accepts this chain”.

A good buying brief records the intended use, known dimensions, required quantity and unresolved questions. It can be short. Its purpose is to prevent an attractive photograph from substituting for a fit check.

Exercise: Choose a hypothetical project. Write a two-sentence brief, then list three details you would need to know before ordering. Leave unknown dimensions blank rather than estimating from an unscaled photograph.

Lesson 2 — Read every number with its label

A number needs a unit and a defined feature. “5 mm” might refer to a diameter, length, opening or another dimension. Check the accompanying description or diagram. If the listing gives several dimensions without explaining their order, ask for clarification.

Keep overall size separate from the clearance needed to connect two parts. An outside dimension does not by itself establish the space inside an opening. Equally, a pendant body measurement may exclude its suspension. Record exactly which feature the supplier describes.

Unit conversion helps comparisons: 1 cm equals 10 mm. A 2 cm dimension is therefore 20 mm. Convert units first, then compare the same feature. Do not treat a nominal measurement as a guarantee that two components will fit; shape, tolerances and the actual connection also matter.

Exercise: Find a dimension on each listing. Write “number + unit + measured feature”. Mark any missing feature description as a question.

Lesson 3 — Quantity, material and finish

Check whether the offer is for one component, a pair, a pack, a length or another stated unit. The photograph may show several items for illustration. Use the written supply quantity and ask if it is unclear.

Read the material and finish as separate fields. A colour description alone does not establish composition. Where a listing describes a plated item, record both the stated base material and coating. Do not shorten a plated-material description in a way that changes what it means.

For a fair price comparison, calculate the price for the same unit and check whether delivery or other charges affect the total. Price per component = pack price divided by components supplied. This arithmetic does not establish that two products are equivalent in construction, quality or suitability.

Lesson 4 — Build a comparison record

Use the same fields for each candidate:

  1. Product name and listing URL.
  2. Intended application stated by the supplier.
  3. Quantity and supply unit.
  4. Dimensions, with each feature identified.
  5. Stated material and finish.
  6. Compatibility information.
  7. Price for a comparable unit.
  8. Unknowns that affect your decision.

Choose only when the information supports the task. If a missing dimension determines fit, it is a decision blocker. A missing decorative detail might matter less. Distinguish what is essential from what is simply interesting.

Worked example — fictional packs

Pack A contains 10 components and costs £4. Pack B contains 20 and costs £7. The component prices are £0.40 and £0.35 respectively. However, only Pack A identifies the opening dimension needed for your project. Pack B is cheaper per item, but its suitability remains unconfirmed.

A useful supplier question would be: “Please confirm the internal opening dimension for this component and whether the stated overall measurement includes the suspension.” Include the listing URL and the dimensions of the part it must connect to.

Practical assignment

Choose two real listings without buying them. Complete the eight-field record for each, calculate a comparable unit price where possible, and write a recommendation of 80–120 words. Explain whether the evidence supports a choice or whether more information is required.

You can practise with findings, tools or listings you already use. This exercise does not require a JTR product.

Optional catalogue exercise

Choose a route that relates to your work, then compare two listings using the eight-field record above. Record the date you checked them; prices and availability can change.

  • Jewellery tools: compare two pack quantities of the same ring sizer or anti-tarnish format. Check the sizing system or dimensions before calculating the price per item.
  • Watch tools: compare two tools by their stated task, working range and supplied contents. A similar appearance does not establish that they are interchangeable.
  • Clock parts & spares: compare the stated part type, dimensions and quantity. Record any missing fit information as a question before choosing a replacement.

For a detail that affects your decision, contact JTR with the listing link, the stated specification and the measurement or application you need confirmed. Browsing is sufficient for this exercise; no purchase is required.

Self-check

  1. A photograph shows six items, but the description says pack of two. Which quantity should you use?
  2. A listing says “8 mm”. What is missing?
  3. How many millimetres are 1.5 cm?
  4. A pack of 25 costs £10. What is the component price?
  5. Does a lower unit price prove that a component is suitable?
  6. How should you record a plated item’s material description?

Answers and explanations

  1. Use the stated pack quantity of two; ask the supplier if the presentation creates uncertainty.
  2. The measured feature, such as overall diameter or opening size. The unit alone is insufficient.
  3. 15 mm: multiply centimetres by 10.
  4. £0.40: divide £10 by 25.
  5. No. Fit, material, construction and intended use still need to satisfy the task.
  6. Retain the stated base material and finish separately, without turning a coating into a solid-material claim.

Completion checklist

Complete the module when your comparison records identify quantities, dimensions, material/finish and unknowns; your arithmetic is correct; and you can explain all six self-check answers. Revisit the relevant lesson for any missing field.

This is a self-directed introductory module, not a professional qualification or a guarantee of compatibility.

Continue to Module 3: Build a Project Brief →

Return to JTR Education · Revisit Module 1

Original JTR learning material. Published 26 October 2026. The pack comparison is fictional. Always check the current specification for the actual product.