Johannsenite is a manganese-rich member of the pyroxene group typically found in contact metamorphic skarn deposits. It usually forms as attractive, radial, or fibrous clusters in shades of light brown or green, and is highly sought after by systematic mineral collectors.
Is this johannsenite?
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 johannsenite with a known reference. Johannsenite 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. Johannsenite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Johannsenite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: light brown, clove brown, grayish green, blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, radial aggregates, fibrous masses.
Often confused with
Johannsenite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside johannsenite
Minerals reported to co-occur with johannsenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaMnSi₂O₆
- Mohs hardness
- 6
- Density
- 3.5 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Radial Aggregates, Fibrous Masses
- Cleavage
- Good in Two Directions At Nearly 90 Degrees
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Skarn Deposits and Hydrothermal Veins
- Typical price
- $20-150 for specimens depending on crystal quality
Where rockhounds find johannsenite
Classic worldwide localities
- Morelos, Mexico
- Franklin, New Jersey, USA
- Tuscany, Italy
- Hokkaido, Japan
Field-hunting tip
Look in skarn deposits and hydrothermal veins country — that is the host setting where johannsenite typically forms. If you start seeing rhodochrosite, calcite, quartz in float, you are in the right ground. Field specimens usually show a prismatic crystals, radial aggregates, fibrous masses habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find johannsenite on the map
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