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 — that is 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?+
What is clinosulphur used for?+
Find clinosulphur on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
