Juonniite is a very rare phosphate mineral typically found as small, bright orange to pale yellow bladed crystals within granite pegmatites. It is primarily known from the Viitaniemi pegmatite in Finland, occurring in association with other phosphate species. Due to its extreme rarity, it is almost exclusively sought after by advanced systematic mineral collectors.

Hardness

3-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrare

Juonniite

Hardness: 3-4
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this juonniite?

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 juonniite with a known reference. Juonniite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Juonniite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Juonniite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: bright orange, pale yellow, yellowish brown, gray.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: bladed crystals.

Often confused with

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

Often found alongside juonniite

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

All properties

Chemical formula: CaMg₂(H₂O)₂(PO₄)₂(OH)₂
Mohs hardness: 3-4
Density: 2.44 g/cm³
Colors: Bright Orange Pale Yellow Yellowish Brown Gray
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Bladed Crystals
Cleavage: Good
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites

Where rockhounds find juonniite

Classic worldwide localities

Viitaniemi pegmatite, Eräjärvi, Orivesi, Finland

Field-hunting tip

Look in granite pegmatites country, the host setting where juonniite typically forms. If you start seeing beryl, triphylite, quartz in float, you are in the right ground. Field specimens usually show a bladed crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify juonniite?+

Mohs hardness is 3-4. It typically shows a vitreous luster. The streak is white. Common colors include bright orange, pale yellow, yellowish brown, gray.

Where is juonniite found?+

Notable localities include Viitaniemi pegmatite, Eräjärvi, Orivesi, Finland.

What rocks look like juonniite?+

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

What minerals are found with juonniite?+

Juonniite commonly co-occurs with Beryl, Triphylite, Quartz, Muscovite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does juonniite form in?+

Juonniite typically forms in granite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is juonniite used for?+

Juonniite is used in collector.

Find juonniite on the map

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