I built/maintain FacetLab, a free browser-based WebGL simulator for learning the diamond 4Cs through play.

Instead of reading a static explanation of cut, colour, clarity and carat, learners can inspect a rough crystal, choose an orientation, polish facets, and then review a simple 4Cs scorecard.

Live simulator: https://4cs.co.za/diamond-polishing-game/

Source code: https://github.com/nichesza-max/facetlab

The project is educational only, not appraisal or pricing advice. It is meant as an interactive teaching aid for jewellery beginners, STEM/resource directories, and anyone curious about how visual trade-offs affect a finished stone.