# Pyrite vs. chalcopyrite: how to tell them apart

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

## Summary

Pyrite and chalcopyrite are brassy sulfides that often occur together. Pyrite is paler, harder, and commonly cubic; chalcopyrite is deeper yellow, softer, more often massive, and frequently develops colorful tarnish.

## Bottom line

Use hardness and form together. Pyrite commonly scratches glass and preserves sharp striated cubes; chalcopyrite is readily scratched by steel and typically occurs as softer irregular grains or masses.

## Side-by-side evidence

- Hardness: Pyrite — Mohs 6 to 6.5; scratches glass Chalcopyrite — Mohs 3.5 to 4; scratched by steel and usually does not scratch glass Interpretation — Hardness is the most dependable field separation.
- Color: Pyrite — Pale brass-yellow, sometimes nearly silvery in strong light Chalcopyrite — Warmer, richer brass-yellow Interpretation — Color supports the identification but changes with lighting and tarnish.
- Crystal habit: Pyrite — Cubes, pyritohedra, and angular grains; cube faces may be striated Chalcopyrite — Commonly massive or irregular; tetrahedral crystals are possible but less familiar Interpretation — Sharp striated cubes strongly favor pyrite.
- Tarnish and streak: Pyrite — May tarnish, but vivid peacock colors are less typical; dark streak Chalcopyrite — Often purple, blue, or bronze tarnish; greenish-black streak Interpretation — Tarnish is helpful only with hardness because treated specimens are common.

## Field sequence

1. Expose or locate a clean untarnished surface.
2. Test whether a small edge scratches glass.
3. Inspect crystal faces for cubic form and alternating striations.
4. Use streak, tarnish, and associated minerals as supporting evidence.

## Limits and cautions

- Both minerals may be intergrown in one specimen.
- Commercial “peacock ore” may be chemically treated chalcopyrite or another copper sulfide.
- Avoid grinding or heating sulfides; their dust and fumes are hazardous.

## Frequently asked questions

### Is chalcopyrite a type of pyrite?

No. Pyrite is iron disulfide, while chalcopyrite is copper iron sulfide with different crystal structure, hardness, and economic significance.

### Which one is copper ore?

Chalcopyrite is a major copper ore mineral. Pyrite may occur in the same deposit but is dominated by iron and sulfur.

### Can pyrite turn rainbow colors?

Pyrite can tarnish, but vivid marketed peacock colors are especially associated with altered or treated copper sulfides. Color alone is insufficient.

## Related identification guides

- Pyrite: https://lithomap.app/resources/mineral-identification/pyrite
- Chalcopyrite: https://lithomap.app/resources/mineral-identification/chalcopyrite

## Authoritative sources

- 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
- Chalcopyrite—Bearer of a Precious, Non-Precious Metal — U.S. Geological Survey: https://www.usgs.gov/publications/chalcopyrite-bearer-a-precious-non-precious-metal

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