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.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Dittmarite

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this dittmarite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch dittmarite with a known reference. Dittmarite sits at Mohs 5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: colorless.
5
Look at form & habit
Crystal 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.

mineral

Struvite

Mohs 2

How to tell apart: Dittmarite is noticeably harder (Mohs 5 vs. 2).

How to tell apart: Dittmarite is noticeably harder (Mohs 5 vs. 2-3).

Compare →

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: 5
Density: 2.15 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals, crusts, prismatic
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: In dryer parts of bat guano in caves

Where rockhounds find dittmarite

Classic worldwide localities

Skipton lava tube caves, 40 km southwest of Ballarat, Victoria, Australia
Arnhem Cave, 150 km east of Windhoek, Namibia
Gcwihaba Cave, 280 km west of Maun, northwestern Botswana

Field-hunting tip

Where it forms: In dryer parts of bat guano in caves. If you start seeing struvite, newberyite, hannayite in float, you are in the right ground. Typical habit: tabular crystals, crusts, prismatic. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify dittmarite?+

Mohs hardness is 5. Luster: vitreous. The streak is white. Common colors include colorless.

Where is dittmarite found?+

Notable localities include Skipton lava tube caves, 40 km southwest of Ballarat, Victoria, Australia; Arnhem Cave, 150 km east of Windhoek, Namibia; Gcwihaba Cave, 280 km west of Maun, northwestern Botswana.

What rocks look like dittmarite?+

Dittmarite is most often confused with Struvite, Hannayite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with dittmarite?+

Dittmarite commonly co-occurs with Struvite, Newberyite, Hannayite, Schertelite, Swaknoite, Mundrabillaite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does dittmarite form in?+

Where it forms: In dryer parts of bat guano in caves. Working float back to the host body is the standard way to chase a fresh occurrence.

What is dittmarite used for?+

Dittmarite is used in collector.

Find dittmarite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.