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 — 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 — Greenalite leaves pale yellow, Glauconite leaves pale green; luster reads resinous on Greenalite and dull on Glauconite.
How to tell apart: Streak differs — 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 — that is 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.
