Flinteite is a rare potassium fluorosilicate typically found as a secondary mineral in volcanic fumaroles. It most commonly occurs as small, delicate tabular crystals often associated with other fluorine-bearing minerals.

Hardness

3.5

Mohs

Luster

Pearly

Streak

White

Transparency

Translucent

mineralrare

Flinteite

Hardness: 3.5
Luster: Pearly
Streak: White
Transparency: Translucent

No image

Is this flinteite?

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 flinteite with a known reference. Flinteite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Flinteite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Flinteite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: white, yellow, brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

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

mineral

Malladrite

Mohs 2

How to tell apart: Flinteite is noticeably harder (Mohs 3.5 vs. 2); luster reads pearly on Flinteite and vitreous on Malladrite.

How to tell apart: Flinteite is noticeably harder (Mohs 3.5 vs. 2); luster reads pearly on Flinteite and vitreous on Hieratite.

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Often found alongside flinteite

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

All properties

Chemical formula: K₂SiF₆
Mohs hardness: 3.5
Density: 2.5 g/cm³
Colors: White Yellow Brown
Streak: White
Luster: Pearly
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Fumarolic Deposits
Typical price: $50-200 per specimen

Where rockhounds find flinteite

Classic worldwide localities

Fumaroles at La Fossa crater, Vulcano, Italy

Field-hunting tip

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

Common questions

How do you identify flinteite?+

Mohs hardness is 3.5. It typically shows a pearly luster. The streak is white. Common colors include white, yellow, brown.

Where is flinteite found?+

Notable localities include Fumaroles at La Fossa crater, Vulcano, Italy.

How much is flinteite worth?+

Typical asking prices fall in the range of $50-200 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is flinteite safe to handle?+

It contains toxic constituents. Contains fluorine; should be handled with care and stored securely to prevent ingestion or inhalation of dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like flinteite?+

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

What minerals are found with flinteite?+

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

What kind of rock does flinteite form in?+

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

What is flinteite used for?+

Flinteite is used in collector.

Find flinteite on the map

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