The four Cs
What carat, color, clarity and cut each measure, how a lab grades them, and how much each one changes the look of a real stone, shown in our 3D Gemstone Simulator. 8 lessons and a course quiz.
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Anatomy of a diamond
Table, crown, pavilion, girdle and culet: what each part of a round brilliant is, how it is measured, and what it does to the light, tested in our Cut Grading Tool and 3D Gemstone Simulator. 9 lessons and a course quiz.
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Reading a grading report
A diamond grading report, line by line: who the stone is, the grades, polish, symmetry and fluorescence, the clarity plot, the proportion diagram and the comments. GIA by default, with IGI's differences noted. 9 lessons and a course quiz.
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Diamond vs moissanite
Two stones that look alike: what each one is, why moissanite throws more fire, doubled facets, weight, color, what the testers say and what the paperwork shows, all tried in our own tools. 10 lessons and a course quiz.
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The history of the brilliant
Six hundred years of diamond cutting, one cut per lesson: from the old single cut of the 1400s to DG-Miliano in 2026. Learn what technology made each cut possible, and measure what it did to brilliance, fire and scintillation in our own tools. 8 lessons and a course quiz.
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Unlock for $10
The bow-tie files
The dark band across an oval, pear or marquise: what a bow-tie is, why it shows in one room and not another, four published explanations put to the test, and the rebuild of a marquise that had one, all in our own tools. 9 lessons and a course quiz.
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