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

No image

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, 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.