Ilesite is a rare manganese-bearing sulfate mineral typically found as secondary crusts or coatings in oxidizing sulfide deposits. It is highly unstable in humid conditions and can easily dehydrate into other sulfate species, so it should be stored in a cool, dry, and airtight container.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareRozenite Group family

Ilesite

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

Is this ilesite?

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 ilesite with a known reference. Ilesite 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. Ilesite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Ilesite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: green, yellowish-green, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: botryoidal, crusts, granular aggregates.

Often confused with

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

Often found alongside ilesite

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

All properties

Chemical formula: (Mn,Zn,Fe)SO₄·4H₂O
Mohs hardness: 2
Density: 2.11 g/cm³
Colors: Green Yellowish-green White
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Botryoidal, Crusts, Granular Aggregates
Cleavage: Good
Rarity: Rare
Uses: Collector
Host rock: Oxidized Hydrothermal Sulfate Zones
Typical price: $20-100 per specimen

Where rockhounds find ilesite

Classic worldwide localities

Bonanza, Colorado, USA
Freiberg, Saxony, Germany
Huanuni, Bolivia

Field-hunting tip

Look in oxidized hydrothermal sulfate zones country — that is the host setting where ilesite typically forms. If you start seeing szomolnokite, melanterite, goethite in float, you are in the right ground. Field specimens usually show a botryoidal, crusts, granular aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ilesite?+

Mohs hardness is 2. It typically shows a vitreous luster. The streak is white. Common colors include green, yellowish-green, white.

Where is ilesite found?+

Notable localities include Bonanza, Colorado, USA; Freiberg, Saxony, Germany; Huanuni, Bolivia.

How much is ilesite worth?+

Typical asking prices fall in the range of $20-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like ilesite?+

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

What minerals are found with ilesite?+

Ilesite commonly co-occurs with Szomolnokite, Melanterite, Goethite, Pyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ilesite form in?+

Ilesite typically forms in oxidized hydrothermal sulfate zones. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ilesite used for?+

Ilesite is used in collector.

Find ilesite on the map

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