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, 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.