Chlorapatite is a rare member of the apatite group characterized by a chlorine-dominant composition. It usually presents as hexagonal prisms or granular masses in metamorphosed limestones and certain igneous environments, and it is visually indistinguishable from other apatite species without chemical analysis.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrareApatite Group family

Chlorapatite

Hardness: ~5
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

Is this chlorapatite?

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 chlorapatite with a known reference. Chlorapatite sits at Mohs ~5, 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: greenish yellow, pinkish white.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: prismatic crystals, massive, granular.

Often confused with

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

Often found alongside chlorapatite

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

All properties

Chemical formula: Ca₅(PO₄)₃Cl
Mohs hardness: ~5
Density: 3.17-3.18 g/cm³
Colors: Greenish yellow Pinkish white
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Hexagonal
Crystal habit: Prismatic crystals, massive, granular
Cleavage: Poor on {0001} and {1010}
Rarity: Rare
Uses: Collector, Scientific research
Host rock: Relatively much rarer than fluorapatite or hydroxylapatite, formed in F-deficient environments

Where rockhounds find chlorapatite

Classic worldwide localities

Fairfax quarry, Centreville, Fairfax Co., and Bull Run quarry, Loudoun Co., Virginia, USA
Stillwater complex, Montana, USA
White Picacho district, Maricopa and Yavapai Cos., Arizona, USA
Bob’s Lake, Frontenac Co., Quebec, Canada
Bushveld complex, Transvaal, South Africa
Angarf-Sud pegmatite, Tazenakht Plain, Morocco

Field-hunting tip

Where it forms: Relatively much rarer than fluorapatite or hydroxylapatite, formed in F-deficient environments. If you start seeing actinolite, diopside, calcite in float, you are in the right ground. Typical habit: prismatic crystals, massive, granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify chlorapatite?+

Mohs hardness is ~5. Luster: vitreous. The streak is white. Common colors include greenish yellow, pinkish white.

Where is chlorapatite found?+

Notable localities include Fairfax quarry, Centreville, Fairfax Co., and Bull Run quarry, Loudoun Co., Virginia, USA; Stillwater complex, Montana, USA; White Picacho district, Maricopa and Yavapai Cos., Arizona, USA; Bob’s Lake, Frontenac Co., Quebec, Canada; Bushveld complex, Transvaal, South Africa.

What rocks look like chlorapatite?+

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

What minerals are found with chlorapatite?+

Chlorapatite commonly co-occurs with Actinolite, Diopside, Calcite, Quartz, Talc, Amphibole. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does chlorapatite form in?+

Where it forms: Relatively much rarer than fluorapatite or hydroxylapatite, formed in F-deficient environments. Working float back to the host body is the standard way to chase a fresh occurrence.

What is chlorapatite used for?+

Chlorapatite is used in collector, scientific research.

Find chlorapatite on the map

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