LithoMap

Mineral identification comparison

Sulfur vs. pyrite: how to tell them apart

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.

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Bright yellow native sulfur coating a gray limestone specimen
SulfurNative element · SPhoto: Darla Sondrol · CC0 1.0
Brassy metallic pyrite crystal specimen
PyriteSulfide mineral · FeS₂Photo: Didier Descouens · CC BY-SA 4.0
Quick answer

The most useful distinction

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

Sulfur and Pyrite comparison table

PropertySulfurPyriteHow to use it
Luster and colorBright yellow with resinous, greasy, or earthy nonmetallic lusterPale brass-yellow with metallic lusterMetallic reflection usually separates pyrite immediately.
HardnessMohs about 1.5 to 2.5; often scratched by a fingernailMohs 6 to 6.5; scratches glassThe large hardness gap is decisive.
StreakWhite to pale yellowGreenish- to brownish-blackPowder colors are sharply different.
Density and habitLightweight; crystals, crusts, coatings, or earthy massesMuch denser; cubes, pyritohedra, nodules, grains, or massesHeft and geometric metallic crystals support the tests.
Field sequence

A practical identification sequence

  1. 1

    Observe whether the surface is metallic or resinous in diffuse light.

  2. 2

    Try a gentle fingernail scratch on an expendable fresh edge.

  3. 3

    Use streak only if necessary and safe.

  4. 4

    Use volcanic, evaporite, or sulfide-deposit context as supporting evidence.

Limits and cautions

Where the distinction gets difficult

  • 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.

Use several independent observations. This comparison supports preliminary field identification, not laboratory confirmation, appraisal, proof of origin, or collecting permission.

Common questions

Sulfur vs. pyrite FAQ

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.

Source basis

Authoritative sources

LithoMap wrote this comparison in original language from the physical properties and geological concepts supported by these public scientific references.

Editorial review: September 17, 2026.

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