Potassic-ferro-ferri-sadanagaite is an extremely rare and complex member of the calcium amphibole subgroup, typically found in high-grade metamorphic environments. It usually occurs as dark, stocky, opaque prismatic crystals within skarn deposits and is often identified only through advanced geochemical analysis due to its visual similarity to common hornblende.
Is this potassic-ferro-ferri-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-ferri-sadanagaite with a known reference. Potassic-ferro-ferri-sadanagaite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 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-ferri-sadanagaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Potassic-ferro-ferri-sadanagaite leaves white, Hornblende leaves grayish-white.
How to tell apart: Streak differs, so Potassic-ferro-ferri-sadanagaite leaves white, Hastingsite leaves greenish gray.
Often found alongside potassic-ferro-ferri-sadanagaite
Minerals reported to co-occur with potassic-ferro-ferri-sadanagaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K(Ca₂)(Fe²⁺₃Fe³⁺₂)(Al₃Si₅O₂₂)(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.4-3.5 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic crystals
- Cleavage
- Perfect in two directions at 56 and 124 degrees
- Rarity
- Rare
- Uses
- Collector
- Host rock
- metamorphic skarns and limestone contact zones
Where rockhounds find potassic-ferro-ferri-sadanagaite
Classic worldwide localities
- Japan
- Italy
- Russia
Field-hunting tip
Where it forms: metamorphic skarns and limestone contact zones. If you start seeing calcite, diopside, phlogopite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify potassic-ferro-ferri-sadanagaite?+
Where is potassic-ferro-ferri-sadanagaite found?+
What rocks look like potassic-ferro-ferri-sadanagaite?+
What minerals are found with potassic-ferro-ferri-sadanagaite?+
What kind of rock does potassic-ferro-ferri-sadanagaite form in?+
What is potassic-ferro-ferri-sadanagaite used for?+
Find potassic-ferro-ferri-sadanagaite on the map
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