Ferronigerite-6N6S is a rare tin-bearing oxide mineral found primarily in granite pegmatites. It usually forms as small, tabular, hexagonal-shaped crystals with a distinctive brown or reddish-brown hue and high hardness.
Is this ferronigerite-6n6s?
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 ferronigerite-6n6s with a known reference. Ferronigerite-6N6S sits at Mohs 8.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: grayish white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to greasy.
- 4Match the color rangeCompare against the expected color range: brown, reddish brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy.
Often confused with
Ferronigerite-6N6S vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ferronigerite-6N6S leaves grayish white, Corundum leaves white; luster reads vitreous to greasy on Ferronigerite-6N6S and adamantine to vitreous; pearly on partings on Corundum.
How to tell apart: Streak differs, so Ferronigerite-6N6S leaves grayish white, Spinel leaves white.
How to tell apart: Streak differs, so Ferronigerite-6N6S leaves grayish white, Gahnite leaves gray.
Often found alongside ferronigerite-6n6s
Minerals reported to co-occur with ferronigerite-6n6s. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Al,Fe,Zn)₃(Al,Sn,Fe)₈O₁₅(OH)
- Mohs hardness
- 8.5
- Density
- 4.51 g/cm³
- Colors
- Streak
- Grayish white
- Luster
- Vitreous to greasy
- Transparency
- Transparent to translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In quartz-sillimanite rocks closely associated with tin-bearing granite pegmatites (Egbe district, Nigeria); in tin-bearing skarns (Mt. Garnet, Australia)
Where rockhounds find ferronigerite-6n6s
Classic worldwide localities
- Distinction of the 24R from the 6H polytype requires that the unit cell be determined, which has been accomplished for the following localities: from the Egbe district, Kabba Province, Nigeria
- Mt. Garnet tin deposits, Queensland, Australia
- Geco Cu–Zn deposit, Manitouwadge district, 80 km north-northeast of Lake Superior, Ontario, Canada
Field-hunting tip
Where it forms: In quartz-sillimanite rocks closely associated with tin-bearing granite pegmatites (Egbe district, Nigeria); in tin-bearing skarns (Mt. Garnet, Australia). If you start seeing gahnite, magnetite, fluorite in float, you are in the right ground. Typical habit: platy. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferronigerite-6n6s?+
Where is ferronigerite-6n6s found?+
What rocks look like ferronigerite-6n6s?+
What minerals are found with ferronigerite-6n6s?+
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Find ferronigerite-6n6s on the map
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