Bosiite is a rare member of the tourmaline group, chemically distinct due to its high ferric iron content. It typically forms as prismatic crystals within pegmatite environments and is primarily sought after by advanced collectors of tourmaline species.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareTourmaline Supergroup family

Bosiite

Hardness: 7
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this bosiite?

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 bosiite with a known reference. Bosiite sits at Mohs 7 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Bosiite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Bosiite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: dark red, brownish red.
5
Look at form & habit
Crystal system: trigonal. Typical habit: prismatic crystals.

Often confused with

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

Often found alongside bosiite

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

All properties

Chemical formula: NaFe³⁺₃(Al₄Mg₂)Si₆O₁₈(BO₃)₃(OH)₃O
Mohs hardness: 7
Density: 3.31 g/cm³
Colors: Dark Red Brownish Red
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Trigonal
Crystal habit: Prismatic Crystals
Cleavage: Indistinct
Rarity: Rare
Uses: Collector
Host rock: Pegmatites
Typical price: $50-300+ per specimen depending on size and quality

Where rockhounds find bosiite

Classic worldwide localities

Bosi, Italy

Field-hunting tip

Look in pegmatites country — that is the host setting where bosiite typically forms. If you start seeing quartz, albite, muscovite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify bosiite?+

Mohs hardness is 7. It typically shows a vitreous luster. The streak is white. Common colors include dark red, brownish red.

Where is bosiite found?+

Notable localities include Bosi, Italy.

How much is bosiite worth?+

Typical asking prices fall in the range of $50-300+ per specimen depending on size and quality. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like bosiite?+

Bosiite is most often confused with Schorl, Foitite, Olenite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with bosiite?+

Bosiite commonly co-occurs with Quartz, Albite, Muscovite, Garnet. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does bosiite form in?+

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

What is bosiite used for?+

Bosiite is used in collector.

Find bosiite on the map

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