Potassic-magnesio-fluoro-arfvedsonite is a complex amphibole group mineral found in alkaline rock environments. Collectors typically look for its dark, elongated prismatic crystals in association with other rare alkaline minerals in syenite complexes.
Is this potassic-magnesio-fluoro-arfvedsonite?
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 potassic-magnesio-fluoro-arfvedsonite with a known reference. Potassic-magnesio-fluoro-arfvedsonite 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. Potassic-magnesio-fluoro-arfvedsonite leaves a grey to pale blue streak.
- 3Read the lusterHold the specimen under a strong light. Potassic-magnesio-fluoro-arfvedsonite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, dark green, dark blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, fibrous, acicular.
Often confused with
Potassic-magnesio-fluoro-arfvedsonite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Potassic-magnesio-fluoro-arfvedsonite leaves grey to pale blue, Arfvedsonite leaves grey to bluish-grey.
How to tell apart: Streak differs — Potassic-magnesio-fluoro-arfvedsonite leaves grey to pale blue, Riebeckite leaves blue-gray.
How to tell apart: Streak differs — Potassic-magnesio-fluoro-arfvedsonite leaves grey to pale blue, Hornblende leaves grayish-white.
Often found alongside potassic-magnesio-fluoro-arfvedsonite
Minerals reported to co-occur with potassic-magnesio-fluoro-arfvedsonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- {(K,Na)Na₂}{Mg₄Fe³⁺}(Si₈O₂₂)(F,OH)₂
- Mohs hardness
- 5-6
- Density
- 3.2-3.4 g/cm³
- Colors
- Streak
- Grey to Pale Blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Fibrous, Acicular
- Cleavage
- Perfect {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks, Syenites, Pegmatites
- Typical price
- $20-150 per specimen depending on size and quality
Where rockhounds find potassic-magnesio-fluoro-arfvedsonite
Classic worldwide localities
- Kola Peninsula, Russia
- Mont Saint-Hilaire, Canada
- Narssârssuk, Greenland
Field-hunting tip
Look in alkaline igneous rocks, syenites, pegmatites country — that is the host setting where potassic-magnesio-fluoro-arfvedsonite typically forms. If you start seeing nepheline, aegirine, microcline in float, you are in the right ground. Field specimens usually show a prismatic crystals, fibrous, acicular habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify potassic-magnesio-fluoro-arfvedsonite?+
Where is potassic-magnesio-fluoro-arfvedsonite found?+
How much is potassic-magnesio-fluoro-arfvedsonite worth?+
What rocks look like potassic-magnesio-fluoro-arfvedsonite?+
What minerals are found with potassic-magnesio-fluoro-arfvedsonite?+
What kind of rock does potassic-magnesio-fluoro-arfvedsonite form in?+
What is potassic-magnesio-fluoro-arfvedsonite used for?+
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