Micheelsenite is an extremely rare phosphate mineral known primarily from the Mont Saint-Hilaire alkaline complex. Collectors prize it for its delicate, acicular, and radiating crystal habits found within cavities of syenite pegmatites.

Hardness

3.5-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrare

Micheelsenite

Hardness: 3.5-4
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

Is this micheelsenite?

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 micheelsenite with a known reference. Micheelsenite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: acicular, fibrous, spherical.

Often confused with

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

Often found alongside micheelsenite

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

All properties

Chemical formula: (Ca,Y)₃Al(PO₃OH)CO₃(OH)₆·12H₂O
Mohs hardness: 3.5-4
Density: 2.15 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Hexagonal
Crystal habit: Acicular, fibrous, spherical
Cleavage: Good on {1010} and {0001}
Rarity: Rare
Uses: Collector
Host rock: A late-stage hydrothermal product in alkaline pegmatite

Where rockhounds find micheelsenite

Classic worldwide localities

Mont Saint-Hilaire, Quebec Canada and the Nanna pegmatite, Narsaarsuup Qaava, South Greenland (type locality)

Field-hunting tip

Where it forms: A late-stage hydrothermal product in alkaline pegmatite. If you start seeing aegirine, albite, ancylite- in float, you are in the right ground. Typical habit: acicular, fibrous, spherical. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify micheelsenite?+

Mohs hardness is 3.5-4. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is micheelsenite found?+

Notable localities include Mont Saint-Hilaire, Quebec Canada and the Nanna pegmatite, Narsaarsuup Qaava, South Greenland (type locality).

What rocks look like micheelsenite?+

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

What minerals are found with micheelsenite?+

Micheelsenite commonly co-occurs with Aegirine, Albite, Ancylite-, Catapleiite, Fluorite, Microcline. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does micheelsenite form in?+

Where it forms: A late-stage hydrothermal product in alkaline pegmatite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is micheelsenite used for?+

Micheelsenite is used in collector.

Find micheelsenite on the map

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