Rankachite is a rare tungsten mineral typically found as small, bright yellow to yellowish-green platy crystals. It is most often discovered in weathered hydrothermal veins associated with other tungsten-bearing species.

Hardness

Mohs

Luster

Subadamantine to Resinous to Dull

Streak

Brown

Transparency

Opaque

mineralrare

Rankachite

Hardness: 2
Luster: Subadamantine to Resinous to Dull
Streak: Brown
Transparency: Opaque

Is this rankachite?

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 rankachite with a known reference. Rankachite 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. Rankachite leaves a brown streak.
3
Read the luster
Hold the specimen under a strong light. Rankachite typically shows a subadamantine to resinous to dull luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-green.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals, radial aggregates.

Often confused with

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

mineral

Anthoinite

Mohs 1

How to tell apart: Rankachite is noticeably harder (Mohs 2 vs. 1); streak differs, so Rankachite leaves brown, Anthoinite leaves white; luster reads subadamantine to resinous to dull on Rankachite and dull on Anthoinite.

Compare →

Often found alongside rankachite

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

All properties

Chemical formula: Ca₀.₅(V⁴⁺,V⁵⁺)(W⁶⁺,Fe³⁺)₂O₈(OH)·2H₂O
Mohs hardness: 2
Density: 4.8 g/cm³
Colors: Yellow Yellowish-green
Streak: Brown
Luster: Subadamantine to Resinous to Dull
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Platy Crystals, Radial Aggregates
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins

Where rockhounds find rankachite

Classic worldwide localities

Schneeberg, Saxony, Germany
Eisenzecher Zug mine, Siegerland, Germany

Field-hunting tip

Look in hydrothermal veins country, the host setting where rankachite typically forms. If you start seeing quartz, goethite, tungstite in float, you are in the right ground. Field specimens usually show a platy crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify rankachite?+

Mohs hardness is 2. It typically shows a subadamantine to resinous to dull luster. The streak is brown. Common colors include yellow, yellowish-green.

Where is rankachite found?+

Notable localities include Schneeberg, Saxony, Germany; Eisenzecher Zug mine, Siegerland, Germany.

Is rankachite safe to handle?+

It contains toxic constituents. Contains tungsten and iron. Always wash hands after handling to avoid ingestion of fine particles. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like rankachite?+

Rankachite is most often confused with Anthoinite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with rankachite?+

Rankachite commonly co-occurs with Quartz, Goethite, Tungstite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does rankachite form in?+

Rankachite typically forms in hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is rankachite used for?+

Rankachite is used in collector.

Find rankachite on the map

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