Samuelsonite is a rare phosphate mineral primarily found in complex granite pegmatites. It typically occurs as small, pale-colored crystals or granular masses associated with other phosphate minerals, making it a prized specimen for advanced systematic mineral collectors.
Is this samuelsonite?
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 samuelsonite with a known reference. Samuelsonite 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. Samuelsonite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Samuelsonite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, pale yellow, white, pinkish.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular to prismatic crystals, often as rounded grains or aggregates.
Often confused with
Samuelsonite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside samuelsonite
Minerals reported to co-occur with samuelsonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ca,Ba)Fe²⁺₂Ca₈Al₂ (PO₄)₁₀(OH)₂
- Mohs hardness
- 5
- Density
- 3.37 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular to Prismatic Crystals, Often as Rounded Grains or Aggregates
- Cleavage
- Good On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per small specimen
Where rockhounds find samuelsonite
Classic worldwide localities
- Tip Top Mine, South Dakota, USA
- Palermo No. 1 Mine, New Hampshire, USA
Field-hunting tip
Look in granite pegmatites country — that is the host setting where samuelsonite typically forms. If you start seeing eosphorite, triphylite, apatite in float, you are in the right ground. Field specimens usually show a tabular to prismatic crystals, often as rounded grains or aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find samuelsonite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
