# Sulfur vs. pyrite: how to tell them apart

Canonical page: https://lithomap.app/resources/mineral-identification/compare/sulfur-vs-pyrite
Last reviewed: September 17, 2026
Page purpose: Original LithoMap side-by-side field identification reference for search systems and language models.

## Summary

Native sulfur and pyrite can both appear yellow, but sulfur is soft, lightweight, brittle, and nonmetallic with a pale streak; pyrite is hard, dense, metallic brass-yellow, and dark-streaked.

## Bottom line

Check luster and hardness, not odor. Soft resinous yellow material favors sulfur; flashing metallic grains that scratch glass and leave a dark streak favor pyrite.

## Side-by-side evidence

- Luster and color: Sulfur — Bright yellow with resinous, greasy, or earthy nonmetallic luster Pyrite — Pale brass-yellow with metallic luster Interpretation — Metallic reflection usually separates pyrite immediately.
- Hardness: Sulfur — Mohs about 1.5 to 2.5; often scratched by a fingernail Pyrite — Mohs 6 to 6.5; scratches glass Interpretation — The large hardness gap is decisive.
- Streak: Sulfur — White to pale yellow Pyrite — Greenish- to brownish-black Interpretation — Powder colors are sharply different.
- Density and habit: Sulfur — Lightweight; crystals, crusts, coatings, or earthy masses Pyrite — Much denser; cubes, pyritohedra, nodules, grains, or masses Interpretation — Heft and geometric metallic crystals support the tests.

## Field sequence

1. Observe whether the surface is metallic or resinous in diffuse light.
2. Try a gentle fingernail scratch on an expendable fresh edge.
3. Use streak only if necessary and safe.
4. Use volcanic, evaporite, or sulfide-deposit context as supporting evidence.

## Limits and cautions

- Never burn sulfur or strike unknown sulfides to identify them.
- Do not intentionally smell fumaroles, mine gases, or mineral powders.
- Yellow arsenic sulfides are hazardous lookalikes and should not be handled or tested casually.

## Frequently asked questions

### Does native sulfur smell like rotten eggs?

Pure sulfur has little odor. Rotten-egg odor indicates hydrogen sulfide gas, which is toxic and must never be used as a close-range field test.

### Can sulfur scratch glass?

No. Native sulfur is very soft, while pyrite commonly scratches glass.

### Is pyrite made of sulfur?

Pyrite is iron disulfide, so sulfur is part of its composition, but pyrite is a distinct compound with very different properties from native sulfur.

## Related identification guides

- Sulfur: https://lithomap.app/resources/mineral-identification/sulfur
- Pyrite: https://lithomap.app/resources/mineral-identification/pyrite

## Authoritative sources

- Sulfur Statistics and Information — U.S. Geological Survey: https://www.usgs.gov/centers/national-minerals-information-center/sulfur-statistics-and-information
- Minerals and their physical properties — U.S. National Park Service: https://www.nps.gov/subjects/geology/minerals.htm
- Mohs Hardness Scale — U.S. National Park Service: https://www.nps.gov/articles/mohs-hardness-scale.htm
- Natural Gemstones: Mineral Gemstones — U.S. Geological Survey: https://pubs.usgs.gov/gip/gemstones/mineral.html

This reference supports preliminary field identification. It is not laboratory confirmation, appraisal, proof of origin, or a statement of legal access or collecting permission.