Stanleyite is a rare hydrated vanadium sulfate mineral typically found as vibrant green, needle-like crystals or crusts. It forms as a secondary mineral in the oxidation zones of vanadium-rich sulfide deposits. Due to its solubility, it is best kept in a dry environment to prevent dehydration.

Hardness

Mohs

Luster

Vitreous

Streak

Pale Green

Transparency

Translucent

mineralrare

Stanleyite

Hardness: 2
Luster: Vitreous
Streak: Pale Green
Transparency: Translucent

Is this stanleyite?

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 stanleyite with a known reference. Stanleyite 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. Stanleyite leaves a pale green streak.
3
Read the luster
Hold the specimen under a strong light. Stanleyite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: bright green, yellow-green.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: acicular crystals, fibrous, crusts.

Often confused with

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

How to tell apart: Streak differs — Stanleyite leaves pale green, Mallardite leaves white.

How to tell apart: Streak differs — Stanleyite leaves pale green, Melanterite leaves white.

Compare →

Often found alongside stanleyite

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

All properties

Chemical formula: V⁴⁺O(SO₄)·5H₂O
Mohs hardness: 2
Density: 3.32 g/cm³
Colors: Bright Green Yellow-green
Streak: Pale Green
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Acicular Crystals, Fibrous, Crusts
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Vanadium-bearing Sulfide Deposits
Typical price: $50-300 per specimen

Where rockhounds find stanleyite

Classic worldwide localities

Ragra mine, Peru
Kazakhstan

Field-hunting tip

Look in oxidized zones of vanadium-bearing sulfide deposits country — that is the host setting where stanleyite typically forms. If you start seeing quisqueite, patronite, melanterite in float, you are in the right ground. Field specimens usually show a acicular crystals, fibrous, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify stanleyite?+

Mohs hardness is 2. It typically shows a vitreous luster. The streak is pale green. Common colors include bright green, yellow-green.

Where is stanleyite found?+

Notable localities include Ragra mine, Peru; Kazakhstan.

How much is stanleyite 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 stanleyite?+

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

What minerals are found with stanleyite?+

Stanleyite commonly co-occurs with Quisqueite, Patronite, Melanterite, Gypsum. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does stanleyite form in?+

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

What is stanleyite used for?+

Stanleyite is used in collector.

Find stanleyite on the map

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