Reaphookhillite is a rare hydrated zinc magnesium phosphate mineral found in cave environments. It typically forms delicate, pale yellow platy crystals associated with other phosphate minerals in host limestone settings.
Is this reaphookhillite?
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 reaphookhillite with a known reference. Reaphookhillite 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. Reaphookhillite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Reaphookhillite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts.
Often confused with
Reaphookhillite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside reaphookhillite
Minerals reported to co-occur with reaphookhillite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₂Mg(PO₄)₂(H₂O)₄
- Mohs hardness
- 2
- Density
- 2.8 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Crusts
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Phosphate-rich Cave Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find reaphookhillite
Classic worldwide localities
- Reaphook Hill, South Australia
Field-hunting tip
Look in phosphate-rich cave deposits country — that is the host setting where reaphookhillite typically forms. If you start seeing hopeite, scholzite, parahopeite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify reaphookhillite?+
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How much is reaphookhillite worth?+
What rocks look like reaphookhillite?+
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Find reaphookhillite on the map
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