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, 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.
