Posnjakite

A variety of Minerals

Posnjakite specimen

What is Posnjakite?

Posnjakite is a hydrated copper sulfate mineral. It was discovered in the Tungsten deposit of Nura-Taldy in Karaganda Region in Kazakhstan and described in 1967 by Aleksandr Ivanovich Komkov (1926–1987) and Yevgenii Ivanovich Nefedov (1910–1976) and named after geochemist Eugene Valdemar Posnjak (1888–1949).

Market Value Factors

Pricing varies for every rock and mineral, so use these universal factors to gauge Posnjakite before comparing listings or appraisals.

Size & Weight

Larger, intact specimens usually command higher prices.

Rarity & Demand

Scarce material or popular varieties sell at a premium.

Condition & Finish

Chips, repairs, and heavy wear lower value; clean prep helps.

Treatment & Provenance

Untreated specimens with documented locality are prized.

Applies to all rocks & minerals.

Posnjakite Localities Map

See where Posnjakite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.

Map preview
North ZoneCentral RidgeSouth Basin

Interactive map layers and collecting notes are available in the app.

Key Characteristics

Formation of Posnjakite

Posnjakite is an uncommon but widespread secondary mineral in the oxidised zone of copper sulfide deposits, which may be of post-mine formation. It is associated with brochantite, langite, devilline, serpierite, woodwardite, wroewolfeite, aurichalcite, azurite, malachite and chalcopyrite.

Quick Facts

Physical Properties

Color
Sky-blue to dark-blue, may be slightly greenish-blue.
Hardness (Mohs)
2 - 3
Density
3.35 g/cm³
Streak
Pale-blue.

Chemical Properties

Chemical Formula
Cu4(SO4)(OH)6 · H2O
Elements
Cu, H, O, S
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Posnjakite FAQs

How do I identify Posnjakite?

Posnjakite can be identified by its hardness of 2 - 3 on the Mohs scale, Sky-blue to dark-blue color. Look for these key characteristics when examining specimens.

What color is Posnjakite?

Posnjakite typically appears in Sky-blue to dark-blue, may be slightly greenish-blue.. Color can vary depending on impurities and formation conditions.

How hard is Posnjakite?

Posnjakite has a hardness of 2 - 3 on the Mohs scale. This makes it a soft mineral that can be scratched easily.

What is the formation of posnjakite of Posnjakite?

Posnjakite is an uncommon but widespread secondary mineral in the oxidised zone of copper sulfide deposits, which may be of post-mine formation. It is associated with brochantite, langite, devilline, serpierite, woodwardite, wroewolfeite, aurichalcite, azurite, malachite and chalcopyrite.

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