Clinosulfur is a high-temperature polymorph of elemental sulfur that forms monoclinic crystals, often as a result of rapid cooling near volcanic vents. It is structurally unstable at room temperature and typically reverts to the more common orthorhombic sulfur form over time, making it a challenging and rare acquisition for mineral collectors.
Is this clinosulphur?
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 clinosulphur with a known reference. Clinosulphur 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. Clinosulphur leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Clinosulphur typically shows a resinous luster.
- 4Match the color rangeCompare against the expected color range: yellow, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular crystals, encrustations, prismatic.
Often confused with
Clinosulphur vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside clinosulphur
Minerals reported to co-occur with clinosulphur. 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
- 2.07 g/cm³
- Colors
- Streak
- White
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular Crystals, Encrustations, Prismatic
- Cleavage
- Poor
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Volcanic Fumaroles, Hydrothermal Veins
- Typical price
- $20-150 for rare specimen-grade crystals
Where rockhounds find clinosulphur
Classic worldwide localities
- Italy
- Japan
- USA
- Indonesia
Field-hunting tip
Look in volcanic fumaroles, hydrothermal veins country, the host setting where clinosulphur typically forms. If you start seeing gypsum, aragonite, celestine in float, you are in the right ground. Field specimens usually show a acicular crystals, encrustations, prismatic habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify clinosulphur?+
Where is clinosulphur found?+
How much is clinosulphur worth?+
What rocks look like clinosulphur?+
What minerals are found with clinosulphur?+
What kind of rock does clinosulphur form in?+
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Find clinosulphur on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
