Rouvilleite is a very rare sodium-calcium carbonate fluoride mineral discovered in the alkaline rocks of Mont Saint-Hilaire. It typically forms small, colorless to white hexagonal tabular crystals that are difficult to distinguish from other carbonates without laboratory analysis. Specimens are highly prized by mineral collectors due to the restricted number of global occurrences.

Hardness

3-3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Rouvilleite

Hardness: 3-3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this rouvilleite?

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

Often confused with

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

mineral

Dawsonite

Mohs 3

How to tell apart: Luster reads vitreous on Rouvilleite and pearly on Dawsonite.

Often found alongside rouvilleite

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

All properties

Chemical formula: Na₃Ca₂(CO₃)₃F
Mohs hardness: 3-3.5
Density: 2.44 g/cm³
Colors: Colorless White Pale Yellow
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Hexagonal
Crystal habit: Tabular Crystals, Massive
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Alkaline Igneous Intrusions
Typical price: $50-300 per specimen depending on crystal quality

Where rockhounds find rouvilleite

Classic worldwide localities

Mont Saint-Hilaire, Quebec, Canada

Field-hunting tip

Look in alkaline igneous intrusions country — that is the host setting where rouvilleite typically forms. If you start seeing calcite, dawsonite, analcime in float, you are in the right ground. Field specimens usually show a tabular crystals, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify rouvilleite?+

Mohs hardness is 3-3.5. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white, pale yellow.

Where is rouvilleite found?+

Notable localities include Mont Saint-Hilaire, Quebec, Canada.

How much is rouvilleite worth?+

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

What rocks look like rouvilleite?+

Rouvilleite is most often confused with Dawsonite, Calcite, Shortite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with rouvilleite?+

Rouvilleite commonly co-occurs with Calcite, Dawsonite, Analcime, Aegirine, Natrolite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does rouvilleite form in?+

Rouvilleite typically forms in alkaline igneous intrusions. Working float back to the host body is the standard way to chase a fresh occurrence.

What is rouvilleite used for?+

Rouvilleite is used in collector.

Find rouvilleite on the map

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