Ferrotaaffeite-6N'3S is an extremely rare beryllium mineral member of the taaffeite group, often found in alluvial deposits or metamorphosed limestone. It is highly prized by collectors for its exceptional hardness and rarity, typically occurring as small, water-worn crystals or rare faceted gems.

Hardness

8-8.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Semitransparent

mineralrareTaaffeite Group family

Ferrotaaffeite-6N'3S

Hardness: 8-8.5
Luster: Vitreous
Streak: White
Transparency: Semitransparent

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Is this ferrotaaffeite-6n'3s?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch ferrotaaffeite-6n'3s with a known reference. Ferrotaaffeite-6N'3S sits at Mohs 8-8.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: light green.
5
Look at form & habit
Crystal system: trigonal. Typical habit: hexagonal, tabular.

Often confused with

Ferrotaaffeite-6N'3S vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Luster reads vitreous on Ferrotaaffeite-6N'3S and adamantine to vitreous; pearly on partings on Corundum.

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Often found alongside ferrotaaffeite-6n'3s

Minerals reported to co-occur with ferrotaaffeite-6n'3s. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: BeFe₂Al₆O₁₂
Mohs hardness: 8-8.5
Density: 4.07 g/cm³
Colors: Light green
Streak: White
Luster: Vitreous
Transparency: Semitransparent
Crystal system: Trigonal
Crystal habit: Hexagonal, tabular
Cleavage: Indistinct
Rarity: Rare
Uses: Collector, Gemstone
Host rock: In the wall zone of a granite pegmatite in “hornblende” gabbro

Where rockhounds find ferrotaaffeite-6n'3s

Classic worldwide localities

Rosendal pegmatite, Kemiö (Kimito) Island, southwestern Finland

Field-hunting tip

Where it forms: In the wall zone of a granite pegmatite in “hornblende” gabbro. If you start seeing quartz, plagioclase, sillimanite in float, you are in the right ground. Typical habit: hexagonal, tabular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ferrotaaffeite-6n'3s?+

Mohs hardness is 8-8.5. Luster: vitreous. The streak is white. Common colors include light green.

Where is ferrotaaffeite-6n'3s found?+

Notable localities include Rosendal pegmatite, Kemiö (Kimito) Island, southwestern Finland.

Is ferrotaaffeite-6n'3s safe to handle?+

Ferrotaaffeite-6N'3S contains beryllium. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like ferrotaaffeite-6n'3s?+

Ferrotaaffeite-6N'3S is most often confused with Spinel, Chrysoberyl, Corundum. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with ferrotaaffeite-6n'3s?+

Ferrotaaffeite-6N'3S commonly co-occurs with Quartz, Plagioclase, Sillimanite, Muscovite, Spessartine-almandine, Chlorite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ferrotaaffeite-6n'3s form in?+

Where it forms: In the wall zone of a granite pegmatite in “hornblende” gabbro. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ferrotaaffeite-6n'3s used for?+

Ferrotaaffeite-6N'3S is used in collector, gemstone.

Find ferrotaaffeite-6n'3s on the map

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