Kuksite is a rare lead zinc tellurate phosphate mineral typically found in the oxidation zones of tellurium-bearing ore deposits. It occurs as small, delicate tabular crystals or crusts, often displaying a distinct yellow to greenish-yellow hue, and is highly sought after by advanced mineral collectors.

Hardness

3-4

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrare

Kuksite

Hardness: 3-4
Luster: Adamantine
Streak: White
Transparency: Transparent

Is this kuksite?

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

Often confused with

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

How to tell apart: Streak differs, so Kuksite leaves white, Eztlite leaves orange; luster reads adamantine on Kuksite and pearly on Eztlite.

Compare →

Often found alongside kuksite

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

All properties

Chemical formula: Pb₃Zn₃(Te⁶⁺O₆)(PO₄)₂(OH)₂
Mohs hardness: 3-4
Density: 6.21 g/cm³
Colors: Gray
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals, Crusts, Aggregates
Cleavage: One, Perfect
Rarity: Rare
Uses: Collector
Host rock: Oxidized Hydrothermal Lead-zinc Deposits

Where rockhounds find kuksite

Classic worldwide localities

Kuranakh gold deposit, central Aldan, Siberia, Russia

Field-hunting tip

Look in oxidized hydrothermal lead-zinc deposits country, the host setting where kuksite typically forms. If you start seeing gold, pyrite, quartz in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kuksite?+

Mohs hardness is 3-4. It typically shows a adamantine luster. The streak is white. Common colors include gray.

Where is kuksite found?+

Notable localities include Kuranakh gold deposit, central Aldan, Siberia, Russia.

Is kuksite safe to handle?+

It contains toxic constituents. Contains lead, handle with care. Avoid ingestion, inhalation of dust, or prolonged skin contact. Wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like kuksite?+

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

What minerals are found with kuksite?+

Kuksite commonly co-occurs with gold, pyrite, quartz, emmonsite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kuksite form in?+

Kuksite typically forms in oxidized hydrothermal lead-zinc deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kuksite used for?+

Kuksite is used in collector.

Find kuksite on the map

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