Usovite is a very rare barium-calcium-magnesium fluoride mineral found primarily in its type locality in Russia. It typically presents as brown to dark brown tabular crystals or massive aggregates within hydrothermal vein deposits.

Hardness

3.5

Mohs

Luster

Vitreous to greasy

Streak

White

Transparency

Opaque, translucent in thin fragments

mineralrare

Usovite

Hardness: 3.5
Luster: Vitreous to greasy
Streak: White
Transparency: Opaque, translucent in thin fragments

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Is this usovite?

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 usovite with a known reference. Usovite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to greasy.
4
Match the color range
Compare against the expected color range: brown, dark brown, yellowish brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: granular, platy.

Often confused with

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

Often found alongside usovite

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

All properties

Chemical formula: Ba₂CaMgAl₂F₁₄
Mohs hardness: 3.5
Density: 4.18 g/cm³
Colors: Brown Dark brown Yellowish brown
Streak: White
Luster: Vitreous to greasy
Transparency: Opaque, translucent in thin fragments
Crystal system: Monoclinic
Crystal habit: Granular, platy
Cleavage: One direction, perfect; another at 44° to the first noted under the microscope
Rarity: Rare
Uses: Collector
Host rock: In a fluorite vein in quartz-mica schists

Where rockhounds find usovite

Classic worldwide localities

Upper Noiby River area, Yenisei region, Siberia, Russia (type locality)

Field-hunting tip

Where it forms: In a fluorite vein in quartz-mica schists. If you start seeing fluorite, calcjarlite, muscovite in float, you are in the right ground. Typical habit: granular, platy. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify usovite?+

Mohs hardness is 3.5. Luster: vitreous to greasy. The streak is white. Common colors include brown, dark brown, yellowish brown.

Where is usovite found?+

Notable localities include Upper Noiby River area, Yenisei region, Siberia, Russia (type locality).

What rocks look like usovite?+

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

What minerals are found with usovite?+

Usovite commonly co-occurs with Fluorite, Calcjarlite, Muscovite, Thorite, Chamosite, Zeolites. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does usovite form in?+

Where it forms: In a fluorite vein in quartz-mica schists. Working float back to the host body is the standard way to chase a fresh occurrence.

What is usovite used for?+

Usovite is used in collector.

Find usovite on the map

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