D'Ansite-(Fe) is an exceptionally rare sulfate mineral found exclusively in active volcanic fumarole environments. It typically forms as small, tabular yellow crystals associated with other volcanic sublimates like chlorothionite.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareD'Ansite Group family

D'Ansite-(Fe)

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this d'ansite-(fe)?

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 d'ansite-(fe) with a known reference. D'Ansite-(Fe) 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. 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: colorless, white.
5
Look at form & habit
Crystal system: cubic. Typical habit: tabular crystals.

Often confused with

D'Ansite-(Fe) vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: D'Ansite-(Fe) is noticeably harder (Mohs 3.5 vs. 2.5).

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Often found alongside d'ansite-(fe)

Minerals reported to co-occur with d'ansite-(fe). Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Na₂₁Fe(SO₄)₁₀Cl₃
Mohs hardness: 3.5
Density: 2.62 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Tabular crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: As encrustations on pyroclastic breccia in volcanic fumaroles; also reported as a secondary mineral (Solvenia)

Where rockhounds find d'ansite-(fe)

Classic worldwide localities

La Fossa crater, Vulcano, Aeolian Islands, Italy, Republic of Slovenia
Mežica, Republic of Slovenia

Field-hunting tip

Where it forms: As encrustations on pyroclastic breccia in volcanic fumaroles; also reported as a secondary mineral (Solvenia). If you start seeing sassolite, adranosite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify d'ansite-(fe)?+

Mohs hardness is 3.5. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is d'ansite-(fe) found?+

Notable localities include La Fossa crater, Vulcano, Aeolian Islands, Italy, Republic of Slovenia; Mežica, Republic of Slovenia.

What rocks look like d'ansite-(fe)?+

D'Ansite-(Fe) is most often confused with D'Ansite-(Mn), Chlorothionite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with d'ansite-(fe)?+

D'Ansite-(Fe) commonly co-occurs with Sassolite, Adranosite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does d'ansite-(fe) form in?+

Where it forms: As encrustations on pyroclastic breccia in volcanic fumaroles; also reported as a secondary mineral (Solvenia). Working float back to the host body is the standard way to chase a fresh occurrence.

What is d'ansite-(fe) used for?+

D'Ansite-(Fe) is used in collector.

Find d'ansite-(fe) on the map

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