Beusite is a relatively rare manganese-dominant phosphate mineral belonging to the triphylite group. It is primarily found as massive or granular aggregates within granite pegmatites and is often difficult to distinguish from associated triphylite without chemical analysis.
Is this beusite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch beusite with a known reference. Beusite sits at Mohs 5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale pink or brown.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: reddish brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: lamellar, prismatic.
Often confused with
Beusite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Beusite leaves pale pink or brown, Triphylite leaves white to grayish white.
How to tell apart: Streak differs, so Beusite leaves pale pink or brown, Lithiophilite leaves white to grayish white.
Often found alongside beusite
Minerals reported to co-occur with beusite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MnMn₂(PO₄)₂
- Mohs hardness
- 5
- Density
- 3.60-3.70 g/cm³
- Colors
- Streak
- Pale pink or brown
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Lamellar, prismatic
- Cleavage
- Good on {010}; fair on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage accessory mineral in complex granite pegmatites
Where rockhounds find beusite
Classic worldwide localities
- Storm Mountain and Crystal Snow pegmatites, Crystal Mountain district, Larimer Co., Colorado, USA
- Los Aleros pegmatite, and at the Amanda and San Salvador pegmatites, San Luis Province, Argentina
- Upper Ross Lake, Yellowknife district, Northwest Territories, and at the Gotcha claim, on an island in Cross Lake, Manitoba, Canada
- Eräjärvi area, Orivesi, Finland
- Tsaobismund pegmatite, 60 km south of Karibib, Namibia
- Kyrk-Bulak, Turkestan Range, Kirgizia
Field-hunting tip
Where it forms: A late-stage accessory mineral in complex granite pegmatites. If you start seeing lithiophilite or triphylite, troilite, sarcopside in float, you are in the right ground. Typical habit: lamellar, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify beusite?+
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Find beusite on the map
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