Hilairite is a rare zirconium silicate mineral discovered in the unique alkaline environment of Mont Saint-Hilaire. Collectors look for its characteristic small, sharp, rhombohedral crystals typically found in vugs within nepheline syenite pegmatites.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Hilairite

Hardness: 4
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this hilairite?

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

Often confused with

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

mineral

Calcite

Mohs 3

How to tell apart: Hilairite is noticeably harder (Mohs 4 vs. 3).

How to tell apart: Eudialyte is the harder of the two (Mohs 5-6 vs. 4).

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Often found alongside hilairite

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

All properties

Chemical formula: Na₂ZrSi₃O₉·3H₂O
Mohs hardness: 4
Density: 2.8 g/cm³
Colors: Brown Yellow Orange Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Rhombohedral Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Alkaline Igneous Pegmatites
Typical price: $50-500 depending on crystal size and clarity

Where rockhounds find hilairite

Classic worldwide localities

Mont Saint-Hilaire, Quebec, Canada
Lovozero Massif, Kola Peninsula, Russia

Field-hunting tip

Look in alkaline igneous pegmatites country — that is the host setting where hilairite typically forms. If you start seeing aegirine, microcline, analcime in float, you are in the right ground. Field specimens usually show a rhombohedral crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify hilairite?+

Mohs hardness is 4. It typically shows a vitreous luster. The streak is white. Common colors include brown, yellow, orange, colorless.

Where is hilairite found?+

Notable localities include Mont Saint-Hilaire, Quebec, Canada; Lovozero Massif, Kola Peninsula, Russia.

How much is hilairite worth?+

Typical asking prices fall in the range of $50-500 depending on crystal size and clarity. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like hilairite?+

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

What minerals are found with hilairite?+

Hilairite commonly co-occurs with Aegirine, Microcline, Analcime, Serandite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does hilairite form in?+

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

What is hilairite used for?+

Hilairite is used in collector.

Find hilairite on the map

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