Sulfur is most easily identified by its vibrant yellow color, resinous luster, and distinct smell when burned. It commonly forms as bright yellow pyramidal crystals or crusts around volcanic vents and within sedimentary evaporite beds.
Is this sulfur?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch sulfur with a known reference. Sulfur sits at Mohs 1.5-2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish brown, yellowish gray, reddish, greenish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive, reniform, stalactitic.
Often confused with
Sulfur vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Sulfur leaves white, Orpiment leaves pale lemon-yellow.
How to tell apart: Sphalerite is the harder of the two (Mohs 3.5-4 vs. 1.5-2.5); streak differs, so Sulfur leaves white, Sphalerite leaves pale brown to pale yellow and white.
Often found alongside sulfur
Minerals reported to co-occur with sulfur. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- S₈
- Mohs hardness
- 1.5-2.5
- Density
- 2.05-2.09 g/cm³
- Streak
- White
- Luster
- Resinous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Massive, reniform, stalactitic
- Cleavage
- Imperfect
- Rarity
- Common
- Uses
- Collector, Industrial
- Host rock
- Volcanic exhalations and bacterial reduction of sulfates in sediments
Where rockhounds find sulfur
7 mapped spotsClassic worldwide localities
- Sicily, Italy
- Poland
- Texas, USA
- Louisiana, USA
- Japan
Field-hunting tip
Where it forms: Volcanic exhalations and bacterial reduction of sulfates in sediments. If you start seeing gypsum, calcite, aragonite in float, you are in the right ground. Typical habit: massive, reniform, stalactitic. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, West Virginia. Start trip planning there.
More sulfur photos
Common questions
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Find sulfur on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
