Franzinite is a rare member of the cancrinite group, typically found as small, prismatic crystals within volcanic ejecta blocks. It is primarily known for its occurrences at the Pitigliano locality in Italy, where it forms in association with other rare silicates.

Hardness

5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareCancrinite Group family

Franzinite

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

Is this franzinite?

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 franzinite with a known reference. Franzinite 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. Franzinite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Franzinite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, pale blue, pale green.
5
Look at form & habit
Crystal system: trigonal. Typical habit: prismatic crystals.

Often confused with

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

How to tell apart: Luster reads vitreous on Franzinite and vitreous to greasy on Nepheline.

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Often found alongside franzinite

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

All properties

Chemical formula: (Na,Ca)₇(Si₆Al₆O₂₄)(SO₄,CO₃,Cl)₂
Mohs hardness: 5-6
Density: 2.42 g/cm³
Colors: Colorless White Pale Blue Pale Green
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Prismatic Crystals
Cleavage: Distinct
Rarity: Rare
Uses: Collector
Host rock: Volcanic Ejecta
Typical price: $50-300 per specimen

Where rockhounds find franzinite

Classic worldwide localities

Pitigliano, Tuscany, Italy

Field-hunting tip

Look in volcanic ejecta country — that is the host setting where franzinite typically forms. If you start seeing sanidine, leucite, vesuvianite 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 franzinite?+

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

Where is franzinite found?+

Notable localities include Pitigliano, Tuscany, Italy.

How much is franzinite worth?+

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

What rocks look like franzinite?+

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

What minerals are found with franzinite?+

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

What kind of rock does franzinite form in?+

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

What is franzinite used for?+

Franzinite is used in collector.

Find franzinite on the map

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