---
title: "3D Gemstone Simulator: meaning in gemology"
description: "The 3D Gemstone Simulator is a free Digital Gemology tool that renders a cut stone as a camera sees it. You choose the cut, gemstone, carat weight, color,…"
url: https://digitalgemology.com/learn/glossary/3d-gemstone-simulator
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

> Markdown copy of https://digitalgemology.com/learn/glossary/3d-gemstone-simulator. 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

[Glossary](https://digitalgemology.com/learn/glossary) · How we measure

# 3D Gemstone Simulator

Also called simulator, gemstone simulator

The 3D Gemstone Simulator is a free Digital Gemology tool that renders a cut stone as a camera sees it. You choose the cut, gemstone, carat weight, color, clarity, cut grade and lighting.

## In more detail

It is for seeing, not scoring. The only figures it reports are the Light Return shares, the cut grade proportions and the size. Its report is a simulation of the geometry, not a grading report.

## How we measure it

The graphics card ray-traces each pixel with full Fresnel reflection, three-color dispersion and body color. Each path takes up to 14 bounces, and a still image refines over up to 64 samples per pixel. In doubly refractive stones it traces both rays, so moissanite's facet edges double. It has ten lighting scenes.

## Related terms

- [Light Return](https://digitalgemology.com/learn/glossary/light-return): Light Return sorts each point of a face-up stone by the direction its light came from. Its four classes, direct, indirect, contrast and leakage, together cover the whole face-up stone.
- [Light map](https://digitalgemology.com/learn/glossary/light-map): A light map is a face-up picture of a cut stone, colored by the direction each point's light came from. Red is direct light, green is indirect light, blue is contrast, and a dark color is leakage.
- [Ray tracing](https://digitalgemology.com/learn/glossary/ray-tracing): Ray tracing follows straight lines of light through a model of a stone. At each facet it applies refraction and reflection, and it records where the light comes from or where it leaves.
- [Fresnel reflection](https://digitalgemology.com/learn/glossary/fresnel-reflection): Fresnel reflection is the share of light that a surface reflects instead of letting through. The Fresnel equations give that share from the two refractive indices, the angle and the polarization.
- [Doubly refractive](https://digitalgemology.com/learn/glossary/doubly-refractive): A doubly refractive stone splits light into two rays that vibrate at right angles and travel at different speeds. Each ray has its own refractive index.
- [Simulator cut grade](https://digitalgemology.com/learn/glossary/simulator-cut-grade): The simulator cut grade shows how a worse make of the same design looks. Each grade moves the crown angle, pavilion angle, girdle, table and culet by a fixed step.

## Learn more

- [3D Gemstone Simulator](https://digitalgemology.com/tools/3d_gemstone_simulator)
- [3D Gemstone Simulator](https://digitalgemology.com/about/how-we-measure/simulator)

[All 328 terms](https://digitalgemology.com/learn/glossary)