Okruschite is a rare calcium manganese beryllium arsenate that forms white imperfect, thick-tabular to blocky aggregates. It occurs in a hydrothermal vein cross-cutting rhyolite. It is associated with braunite and arseniosiderite. It was first described from Fuchs quarry, near Sailauf, Spessart Mountains, Bavaria, Germany.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareFillowite Group family

Okruschite

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

No image

Is this okruschite?

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 okruschite with a known reference. Okruschite 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. Okruschite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Okruschite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: imperfect, thick-tabular to blocky aggregates.

Often confused with

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

mineral

Fillowite

Mohs 4.5

How to tell apart: Fillowite is the harder of the two (Mohs 4.5 vs. 3.5); luster reads vitreous on Okruschite and greasy on Fillowite.

Often found alongside okruschite

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

All properties

Chemical formula: Ca₂Mn²⁺₅Be₄(AsO₄)₆(OH)₄·6H₂O
Mohs hardness: 3.5
Density: 3.33 g/cm³
Colors: White
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Imperfect, Thick-tabular to Blocky Aggregates
Cleavage: Distinct On {010} and Parting On {100}
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites

Where rockhounds find okruschite

Classic worldwide localities

Hagendorf-South pegmatite, Bavaria, Germany

Field-hunting tip

Look in granite pegmatites country, the host setting where okruschite typically forms. If you start seeing triplite, apatite, quartz in float, you are in the right ground. Field specimens usually show a imperfect, thick-tabular to blocky aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify okruschite?+

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

Where is okruschite found?+

Notable localities include Hagendorf-South pegmatite, Bavaria, Germany.

Is okruschite safe to handle?+

It contains toxic constituents. Contains arsenic, which is 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 okruschite?+

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

What minerals are found with okruschite?+

Okruschite commonly co-occurs with Triplite, Apatite, Quartz, Muscovite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does okruschite form in?+

Okruschite typically forms in granite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is okruschite used for?+

Okruschite is used in collector.

Find okruschite on the map

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