Native sulfur is widely recognized by its vibrant yellow color and distinct resinous luster. It forms frequently in volcanic environments around fumaroles or within sedimentary evaporite beds associated with gypsum and halite.
Is this native 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 native sulfur with a known reference. Native 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 to greasy.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-orange, yellow-green, brown, yellowish brown, yellowish gray, reddish, greenish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive, reniform, stalactitic.
Often confused with
Native Sulfur vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Native Sulfur leaves white, Orpiment leaves pale lemon-yellow.
How to tell apart: Streak differs, so Native Sulfur leaves white, Greenockite leaves yellow-orange to brick-red; luster reads resinous to greasy on Native Sulfur and adamantine to resinous on Greenockite.
How to tell apart: Sphalerite is the harder of the two (Mohs 3.5-4 vs. 1.5-2.5); streak differs, so Native Sulfur leaves white, Sphalerite leaves pale brown to pale yellow and white.
Often found alongside native sulfur
Minerals reported to co-occur with native sulfur. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- S
- Mohs hardness
- 1.5-2.5
- Density
- 2.07 g/cm³
- Streak
- White
- Luster
- Resinous to greasy
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Massive, reniform, stalactitic
- Cleavage
- Imperfect on {001}, {110}, {111}; parting on {111}
- Rarity
- Common
- Uses
- Collector, Industrial
- Host rock
- A sublimation product at volcanic fumaroles; a product of the activity of biological micro-organisms; as a result of low oxidation potential and highly acidic chemical reactions in mineral deposits
Where rockhounds find native sulfur
Classic worldwide localities
- Salt domes, as in Louisiana, especially in the area of Lake Charles, Chalcasieu Parish, and in Texas near Freeport, Brazoria Co., USA
- California, at the Sulfur Bank mercury mine, on Clear Creek, Lake Co. Crystals from quarries at Maybee and Scofield, Monroe Co., Michigan, USA
- Sulfur Mountain, in Yellowstone Park
- Cianciana, Agrigento, and Racalmuto, the source of exceptionally large and fine crystals, Sicily
- Perticara, near Rimini, Marche, Sicily
- Carrara, Tuscany, Sicily
Field-hunting tip
Where it forms: A sublimation product at volcanic fumaroles; a product of the activity of biological micro-organisms; as a result of low oxidation potential and highly acidic chemical reactions in mineral deposits. If you start seeing gypsum, anhydrite, halite in float, you are in the right ground. Typical habit: massive, reniform, stalactitic. Train your eye for that shape before scanning the outcrop.
Common questions
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Find native sulfur on the map
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