Zinkosite is a rare anhydrous zinc sulfate mineral that typically forms as an alteration product of sphalerite in oxidized ore deposits. It is frequently confused with other sulfate or carbonate minerals but can be distinguished by its distinct crystal habit and paragenesis in arid mining environments.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Zinkosite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this zinkosite?

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 zinkosite with a known reference. Zinkosite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Zinkosite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Zinkosite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, colorless, gray.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, massive, granular.

Often confused with

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

mineral

Goslarite

Mohs 2

How to tell apart: Zinkosite is noticeably harder (Mohs 3.5 vs. 2).

How to tell apart: Luster reads vitreous on Zinkosite and adamantine on Anglesite.

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Often found alongside zinkosite

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

All properties

Chemical formula: ZnSO₄
Mohs hardness: 3.5
Density: 3.74 g/cm³
Colors: White Colorless Gray
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals, Massive, Granular
Cleavage: Distinct
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Hydrothermal Zinc Deposits
Typical price: $20-200 per specimen depending on size and provenance

Where rockhounds find zinkosite

Classic worldwide localities

Spain
Germany
Greece

Field-hunting tip

Look in oxidized zones of hydrothermal zinc deposits country — that is the host setting where zinkosite typically forms. If you start seeing sphalerite, galena, smithsonite in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify zinkosite?+

Mohs hardness is 3.5. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless, gray.

Where is zinkosite found?+

Notable localities include Spain; Germany; Greece.

How much is zinkosite worth?+

Typical asking prices fall in the range of $20-200 per specimen depending on size and provenance. Quality, size, and provenance can move individual specimens well outside that range.

Is zinkosite safe to handle?+

It contains toxic constituents. Contains zinc, which can be toxic if ingested or inhaled as dust; wash hands thoroughly after handling and avoid creating dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like zinkosite?+

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

What minerals are found with zinkosite?+

Zinkosite commonly co-occurs with Sphalerite, Galena, Smithsonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does zinkosite form in?+

Zinkosite typically forms in oxidized zones of hydrothermal zinc deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is zinkosite used for?+

Zinkosite is used in collector.

Find zinkosite on the map

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