Beusite-(Ca) is a rare phosphate mineral found primarily in complex granitic pegmatites. It typically occurs as brownish, massive to granular masses and is often chemically associated with other triphylite group members in advanced stages of pegmatite evolution.
Is this beusite-(ca)?
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-(ca) with a known reference. Beusite-(Ca) 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: very pale brown.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: pale brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, granular, or interstitial filling.
Often confused with
Beusite-(Ca) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Beusite-(Ca) leaves very pale brown, Triphylite leaves white to grayish white.
How to tell apart: Streak differs, so Beusite-(Ca) leaves very pale brown, Lithiophilite leaves white to grayish white.
How to tell apart: Streak differs, so Beusite-(Ca) leaves very pale brown, Graftonite leaves white to pale pink.
Often found alongside beusite-(ca)
Minerals reported to co-occur with beusite-(ca). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaMn₂(PO₄)₂
- Mohs hardness
- ~5
- Density
- 3.610 g/cm³
- Colors
- Streak
- Very pale brown
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Massive, granular, or interstitial filling
- Cleavage
- Good on {010} and {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- granitic pegmatites
Where rockhounds find beusite-(ca)
Classic worldwide localities
- Yellowknife pegmatite field, between Upper Ross Lake and Redout Lake, 75 km northeast of Yellowknife and 3.5 km east of the Redout granite, Northwest Territories, Canada
Field-hunting tip
Where it forms: granitic pegmatites. If you start seeing triphylite-lithiophilite, sarcopside in float, you are in the right ground. Typical habit: massive, granular, or interstitial filling. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify beusite-(ca)?+
Where is beusite-(ca) found?+
What rocks look like beusite-(ca)?+
What minerals are found with beusite-(ca)?+
What kind of rock does beusite-(ca) form in?+
What is beusite-(ca) used for?+
Find beusite-(ca) on the map
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