Quenstedtite is a rare hydrated iron sulfate mineral typically found as a secondary product in the oxidized zones of ore deposits. It is known for its distinct pale violet color, though it is highly soluble and must be kept away from humidity to prevent dehydration or degradation.

Hardness

2.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrare

Quenstedtite

Hardness: 2.5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this quenstedtite?

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 quenstedtite with a known reference. Quenstedtite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Quenstedtite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Quenstedtite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: violet, pale lilac, yellowish.
5
Look at form & habit
Crystal system: triclinic. Typical habit: tabular crystals, crusts, granular aggregates.

Often confused with

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

mineral

Copiapite

Mohs 2.5-3

How to tell apart: Streak differs — Quenstedtite leaves white, Copiapite leaves yellow; luster reads vitreous on Quenstedtite and pearly on Copiapite.

Often found alongside quenstedtite

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

All properties

Chemical formula: Fe₂(SO₄)₃·11H₂O
Mohs hardness: 2.5
Density: 2.04 g/cm³
Colors: Violet Pale Lilac Yellowish
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Triclinic
Crystal habit: Tabular Crystals, Crusts, Granular Aggregates
Cleavage: Good On {010}
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Iron-rich Sulfide Deposits
Typical price: $50-300 per specimen depending on size and quality

Where rockhounds find quenstedtite

Classic worldwide localities

Tierra Amarilla, Chile
Chuquicamata, Chile
Alcaparrosa Mine, Chile

Field-hunting tip

Look in oxidized zones of iron-rich sulfide deposits country — that is the host setting where quenstedtite typically forms. If you start seeing copiapite, coquimbite, jarosite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, granular aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify quenstedtite?+

Mohs hardness is 2.5. It typically shows a vitreous luster. The streak is white. Common colors include violet, pale lilac, yellowish.

Where is quenstedtite found?+

Notable localities include Tierra Amarilla, Chile; Chuquicamata, Chile; Alcaparrosa Mine, Chile.

How much is quenstedtite 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 quenstedtite?+

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

What minerals are found with quenstedtite?+

Quenstedtite commonly co-occurs with Copiapite, Coquimbite, Jarosite, Halotrichite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does quenstedtite form in?+

Quenstedtite typically forms in oxidized zones of iron-rich sulfide deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is quenstedtite used for?+

Quenstedtite is used in collector.

Find quenstedtite on the map

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