CDG Practice Test

The Certified Diamond Grader (CDG) course from HRD Antwerp is open to anyone aged 18 or older, with no prior diamond experience required. This page gives candidates free practice sets by topic, three worked questions with full explanations, a study plan, and a summary of how the course is delivered, what it costs and how it is examined.

CDG Exam at a Glance

What changed for CDG in 2026

• Oct 27, 2026: Exam fee (Online Recorded Theory Module) changed to $669 excl. 21% VAT (90 days access) (previously $673 excl. 21% VAT (90 days access)).^[2]

What the CDG is and how it works

According to HRD Antwerp, “Student must successfully complete and pass the required examinations of both modules (online – 1st level and practice course – 2nd level) to earn the prestigious Certified Diamond Grader diploma, all within six months.”^[1]

The Certified Diamond Grader qualification is run by HRD Antwerp. It combines an online theory module, taken live or recorded, with an on-campus Diamond Grading Practical Course that lasts 10 days. The minimum age is 18, and no previous diamond experience is required.

There are two examinations. The online theory exam is level 1 and the practical exam is level 2. You must pass both to earn the diploma, and both must be completed within 6 months.

Fees listed by HRD Antwerp: the Online Live Theory Module is $804 excluding tax. The Online Recorded Theory Module is $669 excluding 21% VAT and includes 90 days of access. To secure your place, HRD Antwerp asks for full payment within 15 days of registration.

The Online Live Theory Module with code CDGOE2604 runs from Nov 2 to Nov 13, 2026, from 10:00 to 13:00 CET.

This page does not state a retake policy, a pass mark or a question count, because we have no verified source for them. Check the official HRD Antwerp course pages for those details and for any change to dates or fees before you register. Our practice questions are written by us and are not real exam questions. Use them to find weak areas, not to predict the exam.

CDG content outline and where to practise each area

The content areas below are copied from the official CDG content outline published by HRD Antwerp. The right-hand column shows which of our practice sets covers it.

Worked examples: how to reason through CDG questions

These are practice questions written for this site, not questions from the real exam. Each explanation shows why the right answer is right and why the others are wrong.

Example 1

Question: A diamond has a large feather inclusion that extends from near the girdle toward the center under 10x magnification. What is the primary grading concern with this inclusion?

1. It only affects color grade, not clarity
2. It poses a durability risk in addition to affecting clarity grade
3. Feathers at the girdle are always graded as external blemishes
4. It automatically qualifies the stone as I1 clarity

Answer: B. It poses a durability risk in addition to affecting clarity grade

Explanation:

B is correct. A feather is a fracture, and one that runs from near the girdle toward the center is a structural weakness as well as a clarity characteristic. It can chip or extend during setting or everyday wear, so a grader notes both the clarity effect and the durability risk.

A is wrong because a feather is an inclusion and affects clarity, not color. C is wrong because a feather that reaches into the stone seen at 10x is not simply an external blemish, and no rule says every feather at the girdle is graded that way. D is wrong because no single feature automatically sets a clarity grade. The grade depends on its size, position, visibility and how it combines with other characteristics.

Rule to remember: ask what a feature does to appearance and what it does to the stone's strength.

Example 2

Question: In professional diamond grading, the term 'chain of custody' refers to:

1. The legal ownership history of a diamond
2. The documented tracking of a stone from client receipt through grading to return
3. The list of graders who handled the stone
4. The sequence of grading steps performed on each stone

Answer: B. The documented tracking of a stone from client receipt through grading to return

Explanation:

B is correct. Chain of custody is the documented tracking of a stone from the moment the client hands it over, through grading, to its return. Its purpose is accountability and preventing substitution, so every handover is recorded.

A is wrong because ownership history is a question of provenance and title, not of how a laboratory handles a stone. C is wrong because a list of graders is only a part of the record. It does not show where the stone was or when. D is wrong because the order of grading steps describes a workflow, not the movement and control of the stone itself.

Rule to remember: custody is about who held the stone, when, and under what documentation, from intake to return.

Example 3

Question: What is reflective practice in Certified Diamond Grader professional growth?

1. Simply avoiding past mistakes
2. Systematically examining experiences to gain insight and improve future practice
3. Reflecting only on positive outcomes and successes
4. Maintaining a personal journal unrelated to work

Answer: B. Systematically examining experiences to gain insight and improve future practice

Explanation:

B is correct. Reflective practice means systematically examining your experiences, including successes and failures, to gain insight and improve how you work in future.

A is wrong because avoiding past mistakes is a passive aim. It does not involve analysing why something happened. C is wrong because looking only at positive outcomes leaves out the cases that teach the most, and it gives a skewed picture of your own work. D is wrong because a journal unrelated to work may be personal, but it does not feed back into professional performance.

Rule to remember: reflection is structured, covers what went well and what did not, and ends in a change to how you grade or handle stones next time.

How to use these practice tests

Start with the official HRD Antwerp course page so you know how the theory module and the practical course fit together, and what the dates and fees are. Then work through our practice sets in the order of the official content areas: optics, physics and weighing; color, clarity and plotting; then cut grading, fancy shapes and commercial security.

For each set, answer without looking anything up, then read every explanation, including those for questions you got right. Write down the rule behind each miss in one line and keep those lines in a single notes file. Revisit the notes after each set, not just at the end.

Use the worked questions above as a model for how to read the options. Ask why each wrong option is wrong, not only why the right one is right. Add the sets on laboratory reports, documentation and ethics once the core grading topics feel steady, because they are part of how a grader works day to day.

Treat the practical course as separate preparation. Our sets are theory only and cannot replace hands-on grading. Near your test date, repeat the sets where you made the most mistakes and rely on the official material for anything we do not cover.

Sources & last verified

1. HRD Antwerp — number of questions, exam fee, validity, delivery (official source). “Student must successfully complete and pass the required examinations of both modules (online – 1st level and practice course – 2nd level) to earn the…” Verified Oct 27, 2026.
2. HRD Antwerp — exam fee (official source). “TUITION INVESTMENT $ 669 Original price was: $669. $ 669 Current price is: $669. $ 669 (Excl. 21% VAT)” Verified Oct 27, 2026.
3. HRD Antwerp — other (official source). “module 1 optics physics & the foundations of weighing” Verified Oct 28, 2026.

How we verify: editorial & fact-checking policy. Report an error: contact us.