Iwateite is an extremely rare phosphate mineral belonging to the triplite-group. It is primarily identified in manganese-rich environments and is found as granular inclusions within specific metamorphic rock formations in Japan.

Hardness

6-6.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareOlivine Group family

Iwateite

Hardness: 6-6.5
Luster: Vitreous
Streak: White
Transparency: Translucent

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Is this iwateite?

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 iwateite with a known reference. Iwateite sits at Mohs 6-6.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Iwateite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Iwateite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, brown.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: granular.

Often confused with

Iwateite vs. its common look-alikes — and how to tell them apart in the field.

Often found alongside iwateite

Minerals reported to co-occur with iwateite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Na₂MnMn(PO₄)₂
Mohs hardness: 6-6.5
Density: 3.55 g/cm³
Colors: Yellow Brown
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Granular
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Manganiferous Silicate Rock
Typical price: $50-300 per specimen

Where rockhounds find iwateite

Classic worldwide localities

Tanohata mine, Iwate Prefecture, Japan

Field-hunting tip

Look in manganiferous silicate rock country — that is the host setting where iwateite typically forms. If you start seeing aegirine, rhodochrosite, quartz in float, you are in the right ground. Field specimens usually show a granular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify iwateite?+

Mohs hardness is 6-6.5. It typically shows a vitreous luster. The streak is white. Common colors include yellow, brown.

Where is iwateite found?+

Notable localities include Tanohata mine, Iwate Prefecture, Japan.

How much is iwateite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like iwateite?+

Iwateite is most often confused with Triplite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with iwateite?+

Iwateite commonly co-occurs with Aegirine, Rhodochrosite, Quartz, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does iwateite form in?+

Iwateite typically forms in manganiferous silicate rock. Working float back to the host body is the standard way to chase a fresh occurrence.

What is iwateite used for?+

Iwateite is used in collector.

Find iwateite on the map

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