Johninnesite is a rare manganese magnesium silicate mineral known primarily from the zinc deposits of Franklin and Sterling Hill. Collectors typically look for its characteristic pink to brownish-pink fibrous or needle-like crystals often found growing in association with other rare fluorescent Franklin minerals.
Is this johninnesite?
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 johninnesite with a known reference. Johninnesite sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light brownish yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: yellow brown.
- 5Look at form & habitCrystal system: triclinic. Typical habit: fibrous, plumose, radial.
Often confused with
Johninnesite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside johninnesite
Minerals reported to co-occur with johninnesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Mn₉Mg₇(AsO₄)₂(Si₆O₁₇)₂(OH)₈
- Mohs hardness
- 5-6
- Density
- 3.48 g/cm³
- Colors
- Streak
- Light brownish yellow
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Fibrous, plumose, radial
- Cleavage
- Good on {100}, poor on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In low-temperature hydrothermal veins cutting metamorphosed Fe-Mn ores
Where rockhounds find johninnesite
Classic worldwide localities
- Kombat mine, 49 km south of Tsumeb, Namibia
Field-hunting tip
Where it forms: In low-temperature hydrothermal veins cutting metamorphosed Fe-Mn ores. If you start seeing kentrolite, rhodonite, richterite in float, you are in the right ground. Typical habit: fibrous, plumose, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify johninnesite?+
Where is johninnesite found?+
Is johninnesite safe to handle?+
What rocks look like johninnesite?+
What minerals are found with johninnesite?+
What kind of rock does johninnesite form in?+
What is johninnesite used for?+
Find johninnesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
