Ferro-edenite is a member of the calcic amphibole group, typically occurring as dark, prismatic crystals in skarns or metamorphosed carbonate rocks. It is visually indistinguishable from many other dark amphiboles without chemical analysis, though its occurrence in alkaline-rich metamorphic environments is a useful diagnostic hint for collectors.
Is this ferro-edenite?
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 ferro-edenite with a known reference. Ferro-edenite 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. Ferro-edenite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Ferro-edenite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, dark brown, dark green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, elongated grains.
Often confused with
Ferro-edenite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Ferro-edenite leaves white, Hornblende leaves grayish-white.
How to tell apart: Streak differs — Ferro-edenite leaves white, Hastingsite leaves white to light gray.
Often found alongside ferro-edenite
Minerals reported to co-occur with ferro-edenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCa₂Fe₅Si₇AlO₂₂(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.3-3.5 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Elongated Grains
- Cleavage
- Perfect Prismatic
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Metamorphosed Limestones, Skarns, Alkaline Igneous Rocks
- Typical price
- $10-60 for small to cabinet specimens
Where rockhounds find ferro-edenite
Classic worldwide localities
- Quebec, Canada
- New York, USA
- Kola Peninsula, Russia
- Vesuvius, Italy
Field-hunting tip
Look in metamorphosed limestones, skarns, alkaline igneous rocks country — that is the host setting where ferro-edenite typically forms. If you start seeing calcite, diopside, magnetite in float, you are in the right ground. Field specimens usually show a prismatic crystals, elongated grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferro-edenite?+
Where is ferro-edenite found?+
How much is ferro-edenite worth?+
What rocks look like ferro-edenite?+
What minerals are found with ferro-edenite?+
What kind of rock does ferro-edenite form in?+
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Find ferro-edenite on the map
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