Greenalite is an iron-rich silicate mineral typically found in sedimentary iron formations and low-grade metamorphic rocks. It rarely forms distinct crystals, usually appearing as fine-grained, earthy, or granular aggregates that can be challenging to distinguish from other iron-bearing phyllosilicates without X-ray diffraction.
Is this greenalite?
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 greenalite with a known reference. Greenalite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Greenalite leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Greenalite typically shows a resinous luster.
- 4Match the color rangeCompare against the expected color range: olive-green, brownish-green, blackish-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: granular, massive, earthy.
Often confused with
Greenalite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Greenalite leaves pale yellow, Chamosite leaves white to pale green; luster reads resinous on Greenalite and pearly on Chamosite.
How to tell apart: Greenalite is noticeably harder (Mohs 3-4 vs. 2); streak differs, so Greenalite leaves pale yellow, Glauconite leaves pale green; luster reads resinous on Greenalite and dull on Glauconite.
How to tell apart: Streak differs, so Greenalite leaves pale yellow, Cronstedtite leaves dark greenish-gray; luster reads resinous on Greenalite and vitreous on Cronstedtite.
Often found alongside greenalite
Minerals reported to co-occur with greenalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Fe²⁺,Fe³⁺)₂₋₃Si₂O₅(OH)₄
- Mohs hardness
- 3-4
- Density
- 2.7-3.0 g/cm³
- Streak
- Pale Yellow
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Granular, Massive, Earthy
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Sedimentary Iron Formations
- Typical price
- $10-50 for small specimens
Where rockhounds find greenalite
3 mapped spotsClassic worldwide localities
- Mesabi Range, Minnesota, USA
- Krivoy Rog, Ukraine
- Gunflint Iron Formation, Ontario, Canada
Field-hunting tip
Look in sedimentary iron formations country, the host setting where greenalite typically forms. If you start seeing magnetite, siderite, quartz in float, you are in the right ground. Field specimens usually show a granular, massive, earthy habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Minnesota. Start trip planning there.
Common questions
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Find greenalite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
