Dittmarite is a rare phosphate mineral typically found in guano-rich cave environments where it forms through the reaction of bat droppings with host rock. It usually appears as small, colorless to white tabular crystals or crusts alongside other phosphate minerals like struvite.
Is this dittmarite?
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 dittmarite with a known reference. Dittmarite 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. Dittmarite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Dittmarite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals, crusts, prismatic.
Often confused with
Dittmarite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside dittmarite
Minerals reported to co-occur with dittmarite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NH₄Mg(PO₄)·H₂O
- Mohs hardness
- 2
- Density
- 1.69 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular Crystals, Crusts, Prismatic
- Cleavage
- Good On {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Guano Deposits in Limestone Caves
- Typical price
- $20-100 micro to thumbnail specimen
Where rockhounds find dittmarite
Classic worldwide localities
- Skipton Caves, Victoria, Australia
- Big Snowy Mountains, Montana, USA
Field-hunting tip
Look in guano deposits in limestone caves country — that is the host setting where dittmarite typically forms. If you start seeing struvite, hannayite, newberyite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, prismatic habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find dittmarite on the map
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