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, 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.
