Yttrotantalite-(Y) is a rare yttrium-tantalum-niobium oxide mineral often found as dark, brownish-black prismatic crystals in pegmatites. It is notable for its heavy density and characteristic radioactive nature, requiring careful handling by collectors. It is typically sought after by mineralogists interested in rare-earth element bearing species.

Hardness

5-5.5

Mohs

Luster

Resinous

Streak

Light Brown

Transparency

Opaque

mineralrareSamarskite Group family

Yttrotantalite-(Y)

Hardness: 5-5.5
Luster: Resinous
Streak: Light Brown
Transparency: Opaque

Is this yttrotantalite-(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 yttrotantalite-(y) with a known reference. Yttrotantalite-(Y) sits at Mohs 5-5.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Yttrotantalite-(Y) leaves a light brown streak.
3
Read the luster
Hold the specimen under a strong light. Yttrotantalite-(Y) typically shows a resinous luster.
4
Match the color range
Compare against the expected color range: black, brown, yellowish-brown.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: prismatic crystals, flattened or wedge-shaped.

Often confused with

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

mineral

Columbium Ore

Mohs 6

How to tell apart: Streak differs — Yttrotantalite-(Y) leaves light brown, Columbium Ore leaves dark red to black; luster reads resinous on Yttrotantalite-(Y) and submetallic on Columbium Ore.

Compare →

Often found alongside yttrotantalite-(y)

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

All properties

Chemical formula: (Y,U,Fe)(Ta,Nb)O₄
Mohs hardness: 5-5.5
Density: 5.5-6.7 g/cm³
Colors: Black Brown Yellowish-brown
Streak: Light Brown
Luster: Resinous
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Prismatic Crystals, Flattened or Wedge-shaped
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites
Typical price: $50-500 thumbnail to cabinet size

Where rockhounds find yttrotantalite-(y)

Classic worldwide localities

Ytterby, Sweden
Moss, Norway
Karelia, Russia
Western Australia

Field-hunting tip

Look in granite pegmatites country — that is the host setting where yttrotantalite-(y) typically forms. If you start seeing beryl, monazite, zircon in float, you are in the right ground. Field specimens usually show a prismatic crystals, flattened or wedge-shaped habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify yttrotantalite-(y)?+

Mohs hardness is 5-5.5. It typically shows a resinous luster. The streak is light brown. Common colors include black, brown, yellowish-brown.

Where is yttrotantalite-(y) found?+

Notable localities include Ytterby, Sweden; Moss, Norway; Karelia, Russia; Western Australia.

How much is yttrotantalite-(y) worth?+

Typical asking prices fall in the range of $50-500 thumbnail to cabinet size. Quality, size, and provenance can move individual specimens well outside that range.

Is yttrotantalite-(y) safe to handle?+

This mineral is radioactive. Contains radioactive elements (uranium and thorium) and should be stored with adequate shielding and kept away from prolonged skin contact or inhalation of dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like yttrotantalite-(y)?+

Yttrotantalite-(Y) is most often confused with Columbium Ore. A quick hardness test and a streak check separate the look-alikes faster than color alone.

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

Yttrotantalite-(Y) commonly co-occurs with Beryl, Monazite, Zircon, Tourmaline. Spotting any of these in float or country rock is a useful trip signal.

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

Yttrotantalite-(Y) typically forms in granite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is yttrotantalite-(y) used for?+

Yttrotantalite-(Y) is used in collector.

Find yttrotantalite-(y) on the map

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