Wesselsite is a rare strontium copper silicate that occurs as vibrant deep purple platy crystals. It is primarily found within the manganese mines of the Kalahari Manganese Field in South Africa, often associated with other rare silicate minerals.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareGillespite Group family

Wesselsite

Hardness: 4
Luster: Vitreous
Streak: White
Transparency: Translucent

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Is this wesselsite?

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

Often confused with

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

How to tell apart: Cuprorivaite is the harder of the two (Mohs 5 vs. 4); streak differs — Wesselsite leaves white, Cuprorivaite leaves light blue.

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Often found alongside wesselsite

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

All properties

Chemical formula: SrCuSi₄O₁₀
Mohs hardness: 4
Density: 3.37 g/cm³
Colors: Deep Purple Violet
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Platy Crystals
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector, Scientific Research
Host rock: Hydrothermal Manganese Deposits
Typical price: $50-500 thumbnail

Where rockhounds find wesselsite

Classic worldwide localities

Wessels Mine, Northern Cape, South Africa

Field-hunting tip

Look in hydrothermal manganese deposits country — that is the host setting where wesselsite typically forms. If you start seeing sugilite, bustamite, oyelite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify wesselsite?+

Mohs hardness is 4. It typically shows a vitreous luster. The streak is white. Common colors include deep purple, violet.

Where is wesselsite found?+

Notable localities include Wessels Mine, Northern Cape, South Africa.

How much is wesselsite worth?+

Typical asking prices fall in the range of $50-500 thumbnail. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like wesselsite?+

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

What minerals are found with wesselsite?+

Wesselsite commonly co-occurs with Sugilite, Bustamite, Oyelite, Xonotlite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does wesselsite form in?+

Wesselsite typically forms in hydrothermal manganese deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is wesselsite used for?+

Wesselsite is used in collector, scientific research.

Find wesselsite on the map

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