Ferrokinoshitalite is a rare barium-rich member of the mica group, typically found in high-grade metamorphic environments. Collectors identify it by its characteristic platy, micaceous habit and distinctive barium-rich composition which separates it from common biotite.
Is this ferrokinoshitalite?
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 ferrokinoshitalite with a known reference. Ferrokinoshitalite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: dark green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular.
Often confused with
Ferrokinoshitalite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ferrokinoshitalite leaves green, Biotite leaves white; luster reads vitreous on Ferrokinoshitalite and splendent to submetallic, vitreous, pearly on cleavage on Biotite.
How to tell apart: Streak differs, so Ferrokinoshitalite leaves green, Phlogopite leaves white; luster reads vitreous on Ferrokinoshitalite and pearly to submetallic on cleavage on Phlogopite.
How to tell apart: Streak differs, so Ferrokinoshitalite leaves green, Kinoshitalite leaves yellow white.
Often found alongside ferrokinoshitalite
Minerals reported to co-occur with ferrokinoshitalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BaFe₃(Si₂Al₂)O₁₀(OH)₂
- Mohs hardness
- 3
- Density
- 3.69 g/cm³
- Colors
- Streak
- Green
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In massive Pb-Zn-Cu-Ag sulfide orebodies in banded iron formation that underwent high-grade metamorphism
Where rockhounds find ferrokinoshitalite
Classic worldwide localities
- Broken Hill mine, near Aggeneys, northern Cape Province, South Africa
Field-hunting tip
Where it forms: In massive Pb-Zn-Cu-Ag sulfide orebodies in banded iron formation that underwent high-grade metamorphism. If you start seeing quartz, magnetite, spessartine-rich garnet in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferrokinoshitalite?+
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What rocks look like ferrokinoshitalite?+
What minerals are found with ferrokinoshitalite?+
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Find ferrokinoshitalite on the map
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