Kayrobertsonite is a rare manganese zinc phosphate mineral discovered in granite pegmatite environments. It typically forms as small, snow-white tabular crystals and is primarily sought by advanced mineral collectors specializing in phosphate species.
Is this kayrobertsonite?
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 kayrobertsonite with a known reference. Kayrobertsonite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Kayrobertsonite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Kayrobertsonite typically shows a silky luster.
- 4Match the color rangeCompare against the expected color range: snow-white.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals.
Often confused with
Kayrobertsonite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside kayrobertsonite
Minerals reported to co-occur with kayrobertsonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn₂Zn₂(PO₄)₂(OH)₂·2H₂O
- Mohs hardness
- 3.5
- Density
- 2.29 g/cm³
- Colors
- Streak
- White
- Luster
- Silky
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Tabular Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
Where rockhounds find kayrobertsonite
Classic worldwide localities
- Tip Top Mine, South Dakota, USA
Field-hunting tip
Look in granite pegmatites country, the host setting where kayrobertsonite typically forms. If you start seeing triphylite, hureaulite, eosphorite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kayrobertsonite?+
Where is kayrobertsonite found?+
What rocks look like kayrobertsonite?+
What minerals are found with kayrobertsonite?+
What kind of rock does kayrobertsonite form in?+
What is kayrobertsonite used for?+
Find kayrobertsonite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
