Ferro-pargasite is a member of the amphibole supergroup, occurring primarily as a dark-colored mineral in calc-silicate metamorphic environments. It typically forms stout, short-prismatic crystals and is often indistinguishable from other amphiboles without specialized chemical testing.
Is this ferro-pargasite?
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-pargasite with a known reference. Ferro-pargasite 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-pargasite leaves a white to pale gray streak.
- 3Read the lusterHold the specimen under a strong light. Ferro-pargasite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, dark green, dark brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, granular, massive.
Often confused with
Ferro-pargasite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Ferro-pargasite leaves white to pale gray, Hornblende leaves grayish-white.
How to tell apart: Streak differs — Ferro-pargasite leaves white to pale gray, Edenite leaves white.
How to tell apart: Streak differs — Ferro-pargasite leaves white to pale gray, Hastingsite leaves white to light gray.
Often found alongside ferro-pargasite
Minerals reported to co-occur with ferro-pargasite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCa₂Fe²⁺₄Al(Si₆Al₂)O₂₂(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.3-3.5 g/cm³
- Streak
- White to Pale Gray
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Granular, Massive
- Cleavage
- Perfect Prismatic
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Metamorphosed Limestones, Skarns, And High-grade Metamorphic Rocks
- Typical price
- $10-100 per specimen depending on crystal size and quality
Where rockhounds find ferro-pargasite
Classic worldwide localities
- Pargas, Finland
- Kola Peninsula, Russia
- Franklin, New Jersey, USA
- Ontario, Canada
Field-hunting tip
Look in metamorphosed limestones, skarns, and high-grade metamorphic rocks country — that is the host setting where ferro-pargasite typically forms. If you start seeing calcite, diopside, phlogopite in float, you are in the right ground. Field specimens usually show a prismatic crystals, granular, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find ferro-pargasite on the map
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