Fantappièite is an exceptionally rare member of the cancrinite group found in volcanic ejected blocks. It typically forms as small, colorless to white prismatic crystals and is primarily known from the unique mineralogical site of Pitigliano in Italy.

Hardness

5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareCancrinite Group family

Fantappièite

Hardness: 5-6
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this fantappièite?

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 fantappièite with a known reference. Fantappièite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Fantappièite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Fantappièite 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: trigonal. Typical habit: prismatic crystals.

Often confused with

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

Often found alongside fantappièite

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

All properties

Chemical formula: (Na,Ca)₈(Si₆Al₆O₂₄)(SO₄,CO₃,Cl)₂
Mohs hardness: 5-6
Density: 2.35 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Prismatic Crystals
Cleavage: Good
Rarity: Rare
Uses: Collector
Host rock: Volcanic Ejecta
Typical price: n/a

Where rockhounds find fantappièite

Classic worldwide localities

Pitigliano, Tuscany, Italy

Field-hunting tip

Look in volcanic ejecta country — that is the host setting where fantappièite typically forms. If you start seeing sanidine, leucite, haüyne in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify fantappièite?+

Mohs hardness is 5-6. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is fantappièite found?+

Notable localities include Pitigliano, Tuscany, Italy.

How much is fantappièite worth?+

Typical asking prices fall in the range of n/a. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like fantappièite?+

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

What minerals are found with fantappièite?+

Fantappièite commonly co-occurs with Sanidine, Leucite, Haüyne, Pyroxene. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does fantappièite form in?+

Fantappièite typically forms in volcanic ejecta. Working float back to the host body is the standard way to chase a fresh occurrence.

What is fantappièite used for?+

Fantappièite is used in collector.

Find fantappièite on the map

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