Dessauite-(Y) is an extremely rare member of the crichtonite group, typically black to ash-gray. It occurs as tabular crystals in calcite veins cutting dolomite. It was first described from the Buca della Vena mine, Apuan Alps, Tuscany, Italy. Always handle with care due to its uranium content.

Hardness

6.5-7

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareCrichtonite Group family

Dessauite-(Y)

Hardness: 6.5-7
Luster: Metallic
Streak: Black
Transparency: Opaque

No image

Is this dessauite-(y)?

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 dessauite-(y) with a known reference. Dessauite-(Y) sits at Mohs 6.5-7, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Dessauite-(Y) leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Dessauite-(Y) typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: black, ash-gray.
5
Look at form & habit
Crystal system: trigonal. Typical habit: tabular crystals.

Often confused with

Dessauite-(Y) vs. its common look-alikes, and how to tell them apart in the field.

mineral

Crichtonite

Mohs 5-6

How to tell apart: Luster reads metallic on Dessauite-(Y) and metallic to dull on Crichtonite.

How to tell apart: Streak differs, so Dessauite-(Y) leaves black, Mathiasite leaves brownish black.

Compare →

Often found alongside dessauite-(y)

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

All properties

Chemical formula: Sr(Y,U,Mn)Fe₂(Ti,Fe,Cr,V)₁₈(O,OH)₃₈
Mohs hardness: 6.5-7
Density: 4.68 g/cm³
Colors: Black Ash-gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Trigonal
Crystal habit: Tabular Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Alpine-type Hydrothermal Veins

Where rockhounds find dessauite-(y)

Classic worldwide localities

Buca della Vena mine, Tuscany, Italy

Field-hunting tip

Look in alpine-type hydrothermal veins country, the host setting where dessauite-(y) typically forms. If you start seeing anatase, brookite, hematite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify dessauite-(y)?+

Mohs hardness is 6.5-7. It typically shows a metallic luster. The streak is black. Common colors include black, ash-gray.

Where is dessauite-(y) found?+

Notable localities include Buca della Vena mine, Tuscany, Italy.

Is dessauite-(y) safe to handle?+

This mineral is radioactive. Contains uranium and is radioactive; store it apart from other specimens. Wash hands thoroughly after handling and avoid creating dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like dessauite-(y)?+

Dessauite-(Y) is most often confused with Crichtonite, Lindsleyite, Mathiasite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with dessauite-(y)?+

Dessauite-(Y) commonly co-occurs with Anatase, Brookite, Hematite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does dessauite-(y) form in?+

Dessauite-(Y) typically forms in alpine-type hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is dessauite-(y) used for?+

Dessauite-(Y) is used in collector.

Find dessauite-(y) on the map

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