---
title: "GemCad .asc: meaning in gemology"
description: "GemCad is Robert Strickland's faceting design program for Windows, and .asc is its text design format. An .asc file gives the gear, the refractive index and…"
url: https://digitalgemology.com/learn/glossary/gemcad-asc
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

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[Glossary](https://digitalgemology.com/learn/glossary) · Cutting and files

# GemCad .asc

Also called GemCad, .asc file, .gem file

GemCad is Robert Strickland's faceting design program for Windows, and .asc is its text design format. An .asc file gives the gear, the refractive index and every facet's angle and index.

## In more detail

It is the standard format for sharing faceting designs. GemCad, GemRay and Gem Cut Studio open it. GemCad writes a vertical girdle as −89.99°.

## How we measure it

Our cutting files include a GemCad .asc. Our tools also read your own .asc (text) and .gem (binary) GemCad files.

## Related terms

- [Cutting file](https://digitalgemology.com/learn/glossary/cutting-file): A cutting file is a faceting design: every facet's angle and index, in cutting order, for a faceting machine. It tells a faceter how to cut the stone.
- [GemRay](https://digitalgemology.com/learn/glossary/gemray): GemRay is Robert Strickland's ray tracer for GemCad designs, for Windows. It shows how a finished stone will look and how it darkens as it tilts.
- [Gem Cut Studio](https://digitalgemology.com/learn/glossary/gem-cut-studio): Gem Cut Studio is a faceting design and ray-tracing program for Windows and macOS. It opens GemCad .asc files directly, and its own design files end in .gcs.
- [Index gear](https://digitalgemology.com/learn/glossary/index-gear): An index gear is the toothed wheel on a faceting machine that sets each facet's direction around the stone. Each index is one tooth of the gear.

## Learn more

- [Who uses our files](https://digitalgemology.com/about/files)
- [Your own file](https://digitalgemology.com/about/how-we-measure/your-own-file)

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