Goslarite is a hydrated zinc sulfate that typically forms as a secondary efflorescence in mines where zinc-rich sulfide ores have oxidized. It is highly unstable in dry air and will rapidly dehydrate into a white powder, so collectors must keep specimens in airtight, humidity-controlled containers to maintain their crystal structure.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralcommon

Goslarite

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

Is this goslarite?

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 goslarite with a known reference. Goslarite 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. Goslarite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Goslarite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, blue, green.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: acicular or fibrous crusts, efflorescences, stalactitic.

Often confused with

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

Often found alongside goslarite

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

All properties

Chemical formula: ZnSO₄·7H₂O
Mohs hardness: 2
Density: 1.95-1.97 g/cm³
Colors: Colorless White Blue Green
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Acicular or Fibrous Crusts, Efflorescences, Stalactitic
Cleavage: Perfect On {010}
Rarity: Common
Uses: Collector
Host rock: Oxidized Zones of Zinc-rich Hydrothermal Ore Deposits
Typical price: $10-60 per specimen

Where rockhounds find goslarite

Classic worldwide localities

Goslar, Germany
Chile
Spain
United States
Mexico

Field-hunting tip

Look in oxidized zones of zinc-rich hydrothermal ore deposits country — that is the host setting where goslarite typically forms. If you start seeing sphalerite, pyrite, melanterite in float, you are in the right ground. Field specimens usually show a acicular or fibrous crusts, efflorescences, stalactitic habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify goslarite?+

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

Where is goslarite found?+

Notable localities include Goslar, Germany; Chile; Spain; United States; Mexico.

How much is goslarite worth?+

Typical asking prices fall in the range of $10-60 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is goslarite safe to handle?+

It contains toxic constituents. Contains zinc and sulfates; soluble in water and can cause irritation. Handle with care, avoid ingestion or prolonged skin contact, and store in a sealed container to prevent dehydration and crumbling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like goslarite?+

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

What minerals are found with goslarite?+

Goslarite commonly co-occurs with Sphalerite, Pyrite, Melanterite, Chalcanthite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does goslarite form in?+

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

What is goslarite used for?+

Goslarite is used in collector.

Find goslarite on the map

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