Udinaite is an extremely rare magnesium-aluminum silicate mineral found in high-temperature fumarole deposits. It typically occurs as small, pale yellow octahedral crystals associated with volcanic sublimation products.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareSpinel Group family

Udinaite

Hardness: 6
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this udinaite?

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

Often confused with

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

mineral

Spinel

Mohs 8

How to tell apart: Spinel is the harder of the two (Mohs 8 vs. 6).

How to tell apart: Streak differs, so Udinaite leaves white, Magnesioferrite leaves black; luster reads vitreous on Udinaite and metallic on Magnesioferrite.

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Often found alongside udinaite

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

All properties

Chemical formula: NaMg₄(Al₄Mg₂)Si₂O₁₈F
Mohs hardness: 6
Density: 3.16 g/cm³
Colors: Yellow Pale Yellow
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Octahedral Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Volcanic Fumaroles
Typical price: $100-500 per specimen

Where rockhounds find udinaite

Classic worldwide localities

Tolbachik volcano, Kamchatka, Russia

Field-hunting tip

Look in volcanic fumaroles country, the host setting where udinaite typically forms. If you start seeing tenorite, hematite, langbeinite in float, you are in the right ground. Field specimens usually show a octahedral crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify udinaite?+

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

Where is udinaite found?+

Notable localities include Tolbachik volcano, Kamchatka, Russia.

How much is udinaite worth?+

Typical asking prices fall in the range of $100-500 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like udinaite?+

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

What minerals are found with udinaite?+

Udinaite commonly co-occurs with Tenorite, Hematite, Langbeinite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does udinaite form in?+

Udinaite typically forms in volcanic fumaroles. Working float back to the host body is the standard way to chase a fresh occurrence.

What is udinaite used for?+

Udinaite is used in collector.

Find udinaite on the map

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