Eckermannite is a relatively rare sodium-rich amphibole found in alkaline igneous environments. Collectors look for its characteristic blue to blue-green elongated prismatic crystals, which often form in complex assemblages with other alkaline minerals.
Is this eckermannite?
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 eckermannite with a known reference. Eckermannite 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. Eckermannite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Eckermannite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, blue-green, green, gray-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, acicular, fibrous.
Often confused with
Eckermannite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Eckermannite leaves white, Arfvedsonite leaves grey to bluish-grey.
How to tell apart: Streak differs, so Eckermannite leaves white, Riebeckite leaves blue-gray.
Often found alongside eckermannite
Minerals reported to co-occur with eckermannite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaNa₂(Mg₄Al)Si₈O₂₂(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.1-3.2 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Acicular, Fibrous
- Cleavage
- Perfect in Two Directions
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks, Pegmatites
- Typical price
- $20-100 per specimen depending on crystal size and quality
Where rockhounds find eckermannite
Classic worldwide localities
- Sweden
- Canada
- USA
- Russia
- Norway
Field-hunting tip
Look in alkaline igneous rocks, pegmatites country, the host setting where eckermannite typically forms. If you start seeing nepheline, albite, aegirine in float, you are in the right ground. Field specimens usually show a prismatic crystals, acicular, fibrous habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find eckermannite on the map
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