Falsterite is a very rare hydrated calcium magnesium manganese zinc phosphate mineral discovered in Sweden. It typically forms thin, platy greenish blue crystals that are easily overlooked by collectors due to their small size and nondescript appearance.
Is this falsterite?
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 falsterite with a known reference. Falsterite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale greenish blue.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: greenish blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts.
Often confused with
Falsterite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Phosphophyllite is the harder of the two (Mohs 3-3.5 vs. 2); streak differs, so Falsterite leaves pale greenish blue, Phosphophyllite leaves white.
How to tell apart: Hopeite is the harder of the two (Mohs 3.5 vs. 2); streak differs, so Falsterite leaves pale greenish blue, Hopeite leaves white.
Often found alongside falsterite
Minerals reported to co-occur with falsterite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂MgMn₂(FeFe)₂Zn₄(PO₄)₈(OH)₄·14H₂O
- Mohs hardness
- 2
- Density
- 2.78 g/cm³
- Colors
- Streak
- Pale greenish blue
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy crystals, crusts
- Cleavage
- Perfect on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed as the result of secondary alteration of primary triphylite and associated sphalerite in the core-margin of a well-zoned beryl-phosphate granitic pegmatite
Where rockhounds find falsterite
Classic worldwide localities
- Palermo No. 1 pegmatite, North Groton, Grafton County, New Hampshire and the Estes pegmatite quarry, Baldwin, Cumberland County, Maine, USA
Field-hunting tip
Where it forms: Formed as the result of secondary alteration of primary triphylite and associated sphalerite in the core-margin of a well-zoned beryl-phosphate granitic pegmatite. If you start seeing messelite, mitridatite, phosphophyllite in float, you are in the right ground. Typical habit: platy crystals, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify falsterite?+
Where is falsterite found?+
What rocks look like falsterite?+
What minerals are found with falsterite?+
What kind of rock does falsterite form in?+
What is falsterite used for?+
Find falsterite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
