Boromuscovite is a rare boron-rich member of the mica group, structurally analogous to muscovite. It typically appears as colorless to pale-colored platy crystals or foliated aggregates, usually found in complex pegmatitic or metamorphic environments where boron enrichment occurs.

Hardness

2.5-3

Mohs

Luster

Pearly

Streak

White

Transparency

Transparent

mineralrareMica Group family

Boromuscovite

Hardness: 2.5-3
Luster: Pearly
Streak: White
Transparency: Transparent

Is this boromuscovite?

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 boromuscovite with a known reference. Boromuscovite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Boromuscovite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Boromuscovite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: colorless, white, pale yellow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy, foliated, micaceous masses.

Often confused with

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

Often found alongside boromuscovite

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

All properties

Chemical formula: KAl₂(AlSi₃O₁₀)(OH)₂
Mohs hardness: 2.5-3
Density: 2.8-2.9 g/cm³
Colors: Colorless White Pale Yellow
Streak: White
Luster: Pearly
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Platy, Foliated, Micaceous Masses
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector, Scientific Research
Host rock: Metamorphic Rocks, Pegmatites
Typical price: $20-100 per specimen

Where rockhounds find boromuscovite

Classic worldwide localities

Sarany deposit, Russia
Finland
Brazil

Field-hunting tip

Look in metamorphic rocks, pegmatites country — that is the host setting where boromuscovite typically forms. If you start seeing quartz, feldspar, tourmaline in float, you are in the right ground. Field specimens usually show a platy, foliated, micaceous masses habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify boromuscovite?+

Mohs hardness is 2.5-3. It typically shows a pearly luster. The streak is white. Common colors include colorless, white, pale yellow.

Where is boromuscovite found?+

Notable localities include Sarany deposit, Russia; Finland; Brazil.

How much is boromuscovite worth?+

Typical asking prices fall in the range of $20-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like boromuscovite?+

Boromuscovite is most often confused with Muscovite, Paragonite, Illite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with boromuscovite?+

Boromuscovite commonly co-occurs with Quartz, Feldspar, Tourmaline. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does boromuscovite form in?+

Boromuscovite typically forms in metamorphic rocks, pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is boromuscovite used for?+

Boromuscovite is used in collector, scientific research.

Find boromuscovite on the map

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