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 ~5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light pink.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: violet pink.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive.
Often confused with
Jerrygibbsite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Jerrygibbsite leaves light pink, Chondrodite leaves gray.
How to tell apart: Streak differs, so Jerrygibbsite leaves light pink, Humite leaves white.
How to tell apart: 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
- ~5.5
- Density
- 4.00 g/cm³
- Colors
- Violet pink
- Streak
- Light pink
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Massive
- Cleavage
- Imperfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a metamorphosed stratiform Zn-Mn deposit
Where rockhounds find jerrygibbsite
Classic worldwide localities
- Franklin, Sussex Co., New Jersey, USA
Field-hunting tip
Where it forms: In a metamorphosed stratiform Zn-Mn deposit. If you start seeing franklinite, willemite, zincite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify jerrygibbsite?+
Where is jerrygibbsite found?+
What rocks look like jerrygibbsite?+
What minerals are found with jerrygibbsite?+
What kind of rock does jerrygibbsite form in?+
What is jerrygibbsite used for?+
Find jerrygibbsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
