Potassic-ferro-sadanagaite is an extremely rare member of the amphibole supergroup, characterized by its high potassium and iron content. It typically forms dark, prismatic crystals within skarn environments and high-grade metamorphic rocks. Due to its scarcity, it is highly sought after by systematic mineral collectors and rarely seen in the commercial market.
Is this potassic-ferro-sadanagaite?
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-ferro-sadanagaite with a known reference. Potassic-ferro-sadanagaite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Potassic-ferro-sadanagaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Potassic-ferro-sadanagaite 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.
Often confused with
Potassic-ferro-sadanagaite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Potassic-ferro-sadanagaite leaves white, Hornblende leaves grayish-white.
How to tell apart: Streak differs — Potassic-ferro-sadanagaite leaves white, Hastingsite leaves white to light gray.
Often found alongside potassic-ferro-sadanagaite
Minerals reported to co-occur with potassic-ferro-sadanagaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCa₂(Fe²⁺₃Al₂)(Si₅Al₃)O₂₂(OH)₂
- Mohs hardness
- 6
- Density
- 3.39-3.41 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals
- Cleavage
- Perfect On {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphic Skarns and Amphibolites
- Typical price
- $20-100 per specimen
Where rockhounds find potassic-ferro-sadanagaite
Classic worldwide localities
- Japan
- Italy
- Czech Republic
- USA
Field-hunting tip
Look in metamorphic skarns and amphibolites country — that is the host setting where potassic-ferro-sadanagaite typically forms. If you start seeing calcite, diopside, magnetite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify potassic-ferro-sadanagaite?+
Where is potassic-ferro-sadanagaite found?+
How much is potassic-ferro-sadanagaite worth?+
What rocks look like potassic-ferro-sadanagaite?+
What minerals are found with potassic-ferro-sadanagaite?+
What kind of rock does potassic-ferro-sadanagaite form in?+
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Find potassic-ferro-sadanagaite on the map
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