Montebrasite is a lithium-rich phosphate mineral occurring primarily in granitic pegmatites. It is often found as massive, cleavable blocks and is visually indistinguishable from amblygonite without chemical analysis, as they form a continuous solid solution series.

Hardness

5.5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineraluncommonAmblygonite Group family

Montebrasite

Hardness: 5.5-6
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this montebrasite?

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 montebrasite with a known reference. Montebrasite sits at Mohs 5.5-6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Montebrasite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Montebrasite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, colorless, yellow, greenish, gray.
5
Look at form & habit
Crystal system: triclinic. Typical habit: massive, thick tabular crystals.

Often confused with

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

How to tell apart: Quartz is the harder of the two (Mohs 7 vs. 5.5-6).

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Often found alongside montebrasite

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

All properties

Chemical formula: LiAlPO₄(OH)
Mohs hardness: 5.5-6
Density: 3.0-3.1 g/cm³
Colors: White Colorless Yellow Greenish Gray
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Triclinic
Crystal habit: Massive, Thick Tabular Crystals
Cleavage: Perfect Basal
Rarity: Uncommon
Uses: Collector, Lithium Source
Host rock: Granite Pegmatites
Typical price: $10-100 per specimen

Where rockhounds find montebrasite

Classic worldwide localities

Montebras, France
Minas Gerais, Brazil
Newry, Maine, USA
Black Hills, South Dakota, USA
Karibib, Namibia

Field-hunting tip

Look in granite pegmatites country — that is the host setting where montebrasite typically forms. If you start seeing lepidolite, tourmaline, cassiterite in float, you are in the right ground. Field specimens usually show a massive, thick tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify montebrasite?+

Mohs hardness is 5.5-6. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless, yellow, greenish.

Where is montebrasite found?+

Notable localities include Montebras, France; Minas Gerais, Brazil; Newry, Maine, USA; Black Hills, South Dakota, USA; Karibib, Namibia.

How much is montebrasite worth?+

Typical asking prices fall in the range of $10-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like montebrasite?+

Montebrasite is most often confused with Amblygonite, Feldspar, Quartz. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with montebrasite?+

Montebrasite commonly co-occurs with Lepidolite, Tourmaline, Cassiterite, Quartz, Apatite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does montebrasite form in?+

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

What is montebrasite used for?+

Montebrasite is used in collector, lithium source.

Find montebrasite on the map

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