Stanfieldite is a rare phosphate mineral primarily known for its occurrence in stony-iron meteorites like pallasites. It typically forms as small, microscopic inclusions within the silicate and metallic phases of these extraterrestrial rocks.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareWhitlockite Group family

Stanfieldite

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this stanfieldite?

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 stanfieldite with a known reference. Stanfieldite 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. Stanfieldite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Stanfieldite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, gray.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: anhedral to subhedral grains.

Often confused with

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

Often found alongside stanfieldite

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

All properties

Chemical formula: Ca₄Mg₅(PO₄)₆
Mohs hardness: 5
Density: 3.16 g/cm³
Colors: Colorless White Gray
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Anhedral to Subhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific Research
Host rock: Pallasitic Meteorites
Typical price: n/a (extremely rare meteorite specimen only)

Where rockhounds find stanfieldite

Classic worldwide localities

Springwater pallasite meteorite
Imilac pallasite meteorite

Field-hunting tip

Look in pallasitic meteorites country, the host setting where stanfieldite typically forms. If you start seeing olivine, kamacite, taenite in float, you are in the right ground. Field specimens usually show a anhedral to subhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify stanfieldite?+

Mohs hardness is 5. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white, gray.

Where is stanfieldite found?+

Notable localities include Springwater pallasite meteorite; Imilac pallasite meteorite.

How much is stanfieldite worth?+

Typical asking prices fall in the range of n/a (extremely rare meteorite specimen only). Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like stanfieldite?+

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

What minerals are found with stanfieldite?+

Stanfieldite commonly co-occurs with Olivine, Kamacite, Taenite, Merrillite, Chromite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does stanfieldite form in?+

Stanfieldite typically forms in pallasitic meteorites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is stanfieldite used for?+

Stanfieldite is used in collector, scientific research.

Find stanfieldite on the map

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