Ferruccite is a very rare sodium fluoroborate mineral typically found in volcanic fumaroles. It most commonly appears as small, colorless to white tabular crystals or thin crusts in proximity to other borate minerals.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Ferruccite

Hardness: 2
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this ferruccite?

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 ferruccite with a known reference. Ferruccite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Ferruccite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Ferruccite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, crystalline crusts.

Often confused with

Ferruccite vs. its common look-alikes — and how to tell them apart in the field.

Often found alongside ferruccite

Minerals reported to co-occur with ferruccite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: NaBF₄
Mohs hardness: 2
Density: 2.95 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals, Crystalline Crusts
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Fumarolic Deposits
Typical price: $50-300 for rare micro-specimens

Where rockhounds find ferruccite

Classic worldwide localities

Mount Vesuvius, Italy

Field-hunting tip

Look in fumarolic deposits country — that is the host setting where ferruccite typically forms. If you start seeing avogadrite, hieratite, malladrite in float, you are in the right ground. Field specimens usually show a tabular crystals, crystalline crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ferruccite?+

Mohs hardness is 2. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is ferruccite found?+

Notable localities include Mount Vesuvius, Italy.

How much is ferruccite worth?+

Typical asking prices fall in the range of $50-300 for rare micro-specimens. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like ferruccite?+

Ferruccite is most often confused with Avogadrite, Villiaumite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with ferruccite?+

Ferruccite commonly co-occurs with Avogadrite, Hieratite, Malladrite, Sellaite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ferruccite form in?+

Ferruccite typically forms in fumarolic deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ferruccite used for?+

Ferruccite is used in collector.

Find ferruccite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.