Tantite is a very rare tantalum oxide mineral that typically occurs as small, platy crystals. It is primarily identified through its association with complex granite pegmatites and requires professional laboratory analysis for definitive field identification.

Hardness

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrare

Tantite

Hardness: 7
Luster: Adamantine
Streak: White
Transparency: Transparent

No image

Is this tantite?

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 tantite with a known reference. Tantite sits at Mohs 7, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: adamantine.
4
Match the color range
Compare against the expected color range: colorless.
5
Look at form & habit
Crystal system: triclinic. Typical habit: microscopic crystals.

Often confused with

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

How to tell apart: Tantite is noticeably harder (Mohs 7 vs. 6); streak differs, so Tantite leaves white, Columbite leaves blackish brown; luster reads adamantine on Tantite and submetallic on Columbite.

Compare →

Often found alongside tantite

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

All properties

Chemical formula: Ta₂O₅
Mohs hardness: 7
Density: 8.45 g/cm³
Colors: Colorless
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Triclinic
Crystal habit: Microscopic crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In a granite pegmatite cutting amphibolites (Mt. Vasin-Myl’k, Russia); in a highly fractionated pegmatite (Animikie Red Ace pegmatite, Wisconsin, USA)

Where rockhounds find tantite

Classic worldwide localities

Animikie Red Ace pegmatite, Pine River, Florence Co., Wisconsin, USA
Mt. Vasin-Myl’k, Voron’i massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: In a granite pegmatite cutting amphibolites (Mt. Vasin-Myl’k, Russia); in a highly fractionated pegmatite (Animikie Red Ace pegmatite, Wisconsin, USA). If you start seeing microlite, stibiotantalite, holtite in float, you are in the right ground. Typical habit: microscopic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tantite?+

Mohs hardness is 7. Luster: adamantine. The streak is white. Common colors include colorless.

Where is tantite found?+

Notable localities include Animikie Red Ace pegmatite, Pine River, Florence Co., Wisconsin, USA; Mt. Vasin-Myl’k, Voron’i massif, Kola Peninsula, Russia.

What rocks look like tantite?+

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

What minerals are found with tantite?+

Tantite commonly co-occurs with Microlite, Stibiotantalite, Holtite, Manganotantalite, Wodginite, Tantalian manganotantalite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tantite form in?+

Where it forms: In a granite pegmatite cutting amphibolites (Mt. Vasin-Myl’k, Russia); in a highly fractionated pegmatite (Animikie Red Ace pegmatite, Wisconsin, USA). Working float back to the host body is the standard way to chase a fresh occurrence.

What is tantite used for?+

Tantite is used in collector.

Find tantite on the map

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