Clinohumite is a rare magnesium silicate mineral found primarily in contact metamorphic zones of carbonate rocks. Collectors prize it for its vibrant yellow-to-orange hues and its tendency to display strong yellow fluorescence under longwave ultraviolet light.
Is this clinohumite?
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 clinohumite with a known reference. Clinohumite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Clinohumite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Clinohumite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown, orange.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, granular, massive.
Often confused with
Clinohumite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside clinohumite
Minerals reported to co-occur with clinohumite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₉(SiO₄)₄(F,OH)₂
- Mohs hardness
- 6
- Density
- 3.1-3.3 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Granular, Massive
- Cleavage
- Poor On {001}
- Fluorescence
- Often Fluoresces Yellow Under LW UV
- Rarity
- Rare
- Uses
- Collector, Gemstone
- Host rock
- Metamorphosed Limestone and Dolomite
- Typical price
- $20-200 per gram for gem-quality faceted specimens
Where rockhounds find clinohumite
1 mapped spotsClassic worldwide localities
- Pamir Mountains, Tajikistan
- Kukh-i-Lal, Tajikistan
- Siberia, Russia
- Amity, New York, USA
- Franklin, New Jersey, USA
Field-hunting tip
Look in metamorphosed limestone and dolomite country — that is the host setting where clinohumite typically forms. If you start seeing calcite, dolomite, spinel in float, you are in the right ground. Field specimens usually show a prismatic crystals, granular, massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah — start trip planning there.
Common questions
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Find clinohumite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
