Ferronigerite-2N1S is a rare tin-bearing oxide mineral belonging to the nigerite group. It typically occurs as small, dark hexagonal plates or tabular crystals in pegmatites and metamorphic environments, often requiring microscopic examination for positive identification.
Is this ferronigerite-2n1s?
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-2n1s with a known reference. Ferronigerite-2N1S sits at Mohs 8-9, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow-brown.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: brown, colorless, amber yellow, golden brown, red.
- 5Look at form & habitCrystal system: trigonal. Typical habit: anhedral grains, hexagonal, platy.
Often confused with
Ferronigerite-2N1S vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ferronigerite-2N1S leaves yellow-brown, Gahnite leaves gray.
How to tell apart: Streak differs, so Ferronigerite-2N1S leaves yellow-brown, Corundum leaves white; luster reads vitreous on Ferronigerite-2N1S and adamantine to vitreous; pearly on partings on Corundum.
How to tell apart: Ferronigerite-2N1S is noticeably harder (Mohs 8-9 vs. 5-6); streak differs, so Ferronigerite-2N1S leaves yellow-brown, Hematite leaves cherry-red or reddish brown; luster reads vitreous on Ferronigerite-2N1S and metallic or submetallic to dull on Hematite.
Often found alongside ferronigerite-2n1s
Minerals reported to co-occur with ferronigerite-2n1s. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Al,Fe,Zn)₂(Al,Sn)₆O₁₁(OH)
- Mohs hardness
- 8-9
- Density
- 4.25-4.51 g/cm³
- Colors
- Streak
- Yellow-brown
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Trigonal
- Crystal habit
- Anhedral grains, hexagonal, platy
- Cleavage
- Distinct to perfect on {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In quartz-sillimanite rocks closely associated with tin-bearing granite pegmatites (Egbe district, Nigeria); in riebeckite gneiss (La Guia, Spain)
Where rockhounds find ferronigerite-2n1s
Classic worldwide localities
- Egbe district, Kabba Province, Nigeria
- Caramos mine, Lixa, and other places between Felgueiras and Amarante, Portugal
- La Guia, Vigo, Pontevedra Province, Spain
- Falun, Sweden
- Rosendal pegmatite, Kemiö (Kimito) Island, Finland
- An undefined locality in Siberia, Russia
Field-hunting tip
Where it forms: In quartz-sillimanite rocks closely associated with tin-bearing granite pegmatites (Egbe district, Nigeria); in riebeckite gneiss (La Guia, Spain). If you start seeing quartz, sillimanite, andalusite in float, you are in the right ground. Typical habit: anhedral grains, hexagonal, platy. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferronigerite-2n1s?+
Where is ferronigerite-2n1s found?+
What rocks look like ferronigerite-2n1s?+
What minerals are found with ferronigerite-2n1s?+
What kind of rock does ferronigerite-2n1s form in?+
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Find ferronigerite-2n1s on the map
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