Jerrygibbsite is a rare manganese silicate that is most famously found in the Franklin Mining District. Collectors should look for its distinctive bright orange fluorescence under shortwave UV light, which helps distinguish it from other members of the humite group.
Is this jerrygibbsite?
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 jerrygibbsite with a known reference. Jerrygibbsite sits at Mohs 001, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Jerrygibbsite leaves a light pink streak.
- 3Read the lusterHold the specimen under a strong light. Jerrygibbsite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: violet-pink.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: granular to massive.
Often confused with
Jerrygibbsite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Chondrodite is the harder of the two (Mohs 6-6.5 vs. 001); streak differs, so Jerrygibbsite leaves light pink, Chondrodite leaves gray or yellow; luster reads vitreous on Jerrygibbsite and vitreous to resinous on Chondrodite.
How to tell apart: Humite is the harder of the two (Mohs 6-6.5 vs. 001); streak differs, so Jerrygibbsite leaves light pink, Humite leaves white.
How to tell apart: Clinohumite is the harder of the two (Mohs 6 vs. 001); streak differs, so Jerrygibbsite leaves light pink, Clinohumite leaves white.
Often found alongside jerrygibbsite
Minerals reported to co-occur with jerrygibbsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn₉(SiO₄)₄(OH)₂
- Mohs hardness
- 001
- Density
- 4 g/cm³
- Colors
- Streak
- Light Pink
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Granular to Massive
- Cleavage
- Imperfect
- Fluorescence
- Bright Orange Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Zinc Ore Deposits
Where rockhounds find jerrygibbsite
Classic worldwide localities
- Franklin, New Jersey, USA
- Langban, Sweden
Field-hunting tip
Look in metamorphosed zinc ore deposits country, the host setting where jerrygibbsite typically forms. If you start seeing willemite, franklinite, zincite in float, you are in the right ground. Field specimens usually show a granular to massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify jerrygibbsite?+
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What rocks look like jerrygibbsite?+
What minerals are found with jerrygibbsite?+
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Find jerrygibbsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
