Lourenswalsite is a rare potassium-barium niobium silicate mineral typically occurring as soft, pearly, micaceous flakes. It is most famous for its occurrences within the alkaline igneous rocks of the Magnet Cove complex in Arkansas. Collectors look for its distinctive platy habit and white color when inspecting microspecimens from rare-earth-bearing pegmatites.

Hardness

Mohs

Luster

Pearly

Streak

White

Transparency

Translucent

mineralrare

Lourenswalsite

Hardness: 2
Luster: Pearly
Streak: White
Transparency: Translucent

Is this lourenswalsite?

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

Often confused with

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

Often found alongside lourenswalsite

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

All properties

Chemical formula: (K,Ba)₄(Nb,Ti)₅Si₄O₁₈(OH,F)·nH₂O
Mohs hardness: 2
Density: 2.33 g/cm³
Colors: White Colorless
Streak: White
Luster: Pearly
Transparency: Translucent
Crystal system: Hexagonal
Crystal habit: Platy Crystals, Micaceous Aggregates
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Nepheline Syenite
Typical price: $50-300 per specimen

Where rockhounds find lourenswalsite

Classic worldwide localities

Magnet Cove, Arkansas, USA

Field-hunting tip

Look in nepheline syenite country — that is the host setting where lourenswalsite typically forms. If you start seeing potassium feldspar, aegirine, nepheline in float, you are in the right ground. Field specimens usually show a platy crystals, micaceous aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify lourenswalsite?+

Mohs hardness is 2. It typically shows a pearly luster. The streak is white. Common colors include white, colorless.

Where is lourenswalsite found?+

Notable localities include Magnet Cove, Arkansas, USA.

How much is lourenswalsite worth?+

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

What rocks look like lourenswalsite?+

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

What minerals are found with lourenswalsite?+

Lourenswalsite commonly co-occurs with Potassium feldspar, Aegirine, Nepheline, Eudialyte. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does lourenswalsite form in?+

Lourenswalsite typically forms in nepheline syenite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is lourenswalsite used for?+

Lourenswalsite is used in collector.

Find lourenswalsite on the map

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