--- title: "The history of the brilliant quiz" description: "A 13-question quiz on the history of the brilliant, from the old single cut to DG-Miliano, from Digital Gemology's The history of the brilliant course. See whether you are right as you go, with an explanation for every answer." url: https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01 --- > Markdown copy of https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant. Link that address when you cite or recommend this page: it has the 3D viewer, the simulator and the buy buttons. > Site index: https://digitalgemology.com/llms.txt [Courses](https://digitalgemology.com/skool) # The history of the brilliant: course quiz Thirteen questions on lessons 1 to 8 Eleven questions across the whole course, then a two-picture round. Questions 9 to 11 combine lessons. Pick an answer, and the question marks itself. For a question that you answer in your own words, think of your answer first. Then show our answer and say whether you had it. Nothing is saved or sent. ## Questions 1. Question 1: In the 1400s, how did cutters make the facets of a diamond? ### Show the answer **b**: Only diamond can grind diamond. Saws and bruting machines came centuries later (lessons 1, 5 and 6). 2. Question 2: The old single cut scores the most fire in this course (84) but only 72 for brilliance. Why doesn't that mean it shows the most color? ### Show the answer **b**: Read the scores as rough percentages: 84% of a smaller amount of returned light. The T73 returns more light (93), so more color in total (lesson 1). 3. Question 3: Why did the rose cut lose out to the brilliant? ### Show the answer **b**: Equal entry and exit angles send the colors out parallel (lesson 2). 4. Question 4: Which cut is the first with the crown of a modern round brilliant (8 bezels, 8 stars, 16 upper halves)? ### Show the answer **b**: The Peruzzi, or triple cut, late 1600s (lesson 3). 5. Question 5: The old mine is neater and rounder than the Peruzzi, with the same 58 facets. What happens to brilliance, and why? ### Show our answer It falls, 75 → 59, and leakage rises to 32%. Uniform facets are craftsmanship, but nobody calculated the angles yet (lesson 4). 6. Question 6: What did the bruting machine of the 1870s make possible? What did that let cutters change in the stone's depth? ### Show our answer A truly round outline. On a round stone every pavilion main can share one angle, so cutters could make the stone thinner (lesson 5). 7. Question 7: Tolkowsky started his calculation from one property of diamond. Which, and what angle did it give him? ### Show our answer Its refractive index, 2.417. That gives a critical angle of 24° 26′ (lesson 6). 8. Question 8: A seller says a stone with a perfect hearts and arrows pattern must have the best light return. What does the pattern actually show, and what does it leave out? ### Show our answer It shows that opposite facets match in angle and direction: precision. It doesn't show whether the crown and pavilion angles bring the light back. The same perfectly symmetrical T73 loses the pattern in moissanite, and the pattern can appear below the top cut grade (lesson 7). 9. Question 9: The Peruzzi, the old mine and the old European all have the same 58 facets, and score 75, 59 and 90 for brilliance. What changed between them, and which technology made the biggest difference? *(lessons 3, 4, 5)* ### Show our answer The outline and the proportions changed, not the facets. The old mine tidied the Peruzzi by hand and got darker. The bruting machine made the old European round and thinner, and brilliance jumped to 90 (lessons 3, 4 and 5). 10. Question 10: The Peruzzi (1690s) scores 81 for scintillation and the T57 (1919) only 72. A member concludes that old cuts sparkle more. What would you tell them? *(lessons 3, 6)* ### Show our answer The Wheel counts scintillation from the facets. Our Peruzzi model has 74 (with 16 girdle facets) and the T57 has 57 (a knife-edge girdle). The T73 has the same 1919 angles with 16 girdle facets, and it scores 80. And a stone of the 1690s would have had a plain girdle: on 58 facets the formula gives 72, level with the T57 (lessons 3 and 6). 11. Question 11: Put these technologies in the order the course met them, and name the cut each one made possible: the saw and mathematics; 3D ray tracing; the reflector viewer; the polishing wheel with diamond powder; the bruting machine. *(lessons 1, 5, 6, 7, 8)* ### Show our answer Polishing wheel with diamond powder → old single (lesson 1); bruting machine → old European (lesson 5); saw and mathematics → Tolkowsky's T57 (lesson 6); reflector viewer → hearts and arrows (lesson 7); 3D ray tracing → DG-Miliano (lesson 8). ## Picture round 1. Question 12: Name the four cuts in the picture, and say which detail gave each one away. *(lessons 1, 2, 5, 6)* ![Four cuts face up, edges drawn, labeled only A, B, C and D.](https://digitalgemology.com/img/skool/quiz/hb-quiz-which-cut.webp?v=564df424) ### Show our answer A is the **old European**: round, with a small table. B is the **Mazarin**: a cushion outline, 16 facets above the girdle and a wide, open culet. C is the **T73**: round, with the bigger table (53% against the old European's 45%) and the same modern crown of bezels, stars and upper halves. D is the **old single**: an octagon with just 8 facets around the table (lessons 1, 2, 5 and 6). 2. Question 13: Which stone returns more light, and how can you tell from the maps? Name both cuts, and say what changed between them. *(lessons 4, 5)* ![The light maps of two historic cuts face up, labeled only Stone 1 and Stone 2.](https://digitalgemology.com/img/skool/quiz/hb-quiz-which-is-brighter.webp?v=a9e7db4b) ### Show our answer **Stone 2**, the **old European**. Stone 1, the **old mine**, has far more black on its map: light that leaks out through the pavilion. Both have the same 58 facets. The bruting machine made the outline round and the stone thinner. In our census, brilliance jumps from 59 to 90 and leakage falls from 32% to 5% (lessons 4 and 5). ## One lesson at a time Each lesson has five questions. The questions and the answers to pick from come in a new order every time you start. 1. [The old single: eight facets and a lot of fire](https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant/the-old-single-eight-facets-and-a-lot-of-fire) 2. [The Mazarin: the first brilliant](https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant/the-mazarin-the-first-brilliant) 3. [The Peruzzi: today's crown, arriving early](https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant/the-peruzzi-todays-crown-arriving-early) 4. [The old mine: tidier, not brighter](https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant/the-old-mine-tidier-not-brighter) 5. [The old European: when the outline went round](https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant/the-old-european-when-the-outline-went-round) 6. [Tolkowsky 1919: the cut that was calculated](https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant/tolkowsky-1919-the-cut-that-was-calculated) 7. [Hearts and arrows: precision you can see](https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant/hearts-and-arrows-precision-you-can-see) 8. [DG-Miliano: past the 1919 ceiling](https://digitalgemology.com/skool/quiz/the-history-of-the-brilliant/dg-miliano-past-the-1919-ceiling) ## More - [The history of the brilliant: all the lessons](https://digitalgemology.com/learn/historic-cuts) - Next quiz: [The four Cs](https://digitalgemology.com/skool/quiz/the-four-cs) - [All courses](https://digitalgemology.com/skool)