Natronambulite is a rare phosphate mineral found primarily in complex granite pegmatites. It is typically identified by its distinct reddish-brown color and its association with other phosphate minerals in hydrothermal replacement zones.
Is this natronambulite?
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 natronambulite with a known reference. Natronambulite sits at Mohs 5.5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white, with slight orange tint.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: pink orange.
- 5Look at form & habitCrystal system: triclinic. Typical habit: anhedral to subhedral grains, massive.
Often confused with
Natronambulite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside natronambulite
Minerals reported to co-occur with natronambulite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaMn₄Si₅O₁₄(OH)
- Mohs hardness
- 5.5-6
- Density
- 3.51 g/cm³
- Colors
- Pink orange
- Streak
- White, with slight orange tint
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Anhedral to subhedral grains, massive
- Cleavage
- Perfect on {100} and {001}, distinct on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In banded ore of a contact metamorphosed bedded manganese deposit, and as an accessory mineral in an albite-microcline-quartz pegmatite cutting the ore (Tanohata mine, Japan)
Where rockhounds find natronambulite
Classic worldwide localities
- Tanohata mine, Iwate Prefecture, Japan
- Kombat mine, 49 km south of Tsumeb, Namibia
Field-hunting tip
Where it forms: In banded ore of a contact metamorphosed bedded manganese deposit, and as an accessory mineral in an albite-microcline-quartz pegmatite cutting the ore (Tanohata mine, Japan). If you start seeing aegirine, manganoan arfvedsonite, rhodonite in float, you are in the right ground. Typical habit: anhedral to subhedral grains, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify natronambulite?+
Where is natronambulite found?+
What rocks look like natronambulite?+
What minerals are found with natronambulite?+
What kind of rock does natronambulite form in?+
What is natronambulite used for?+
Find natronambulite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
