Stibiotantalite is a rare antimony-tantalum oxide typically found in complex granite pegmatites. It is sought after by collectors for its high refractive index and adamantine luster, often appearing as wedge-shaped or flattened prismatic crystals.

Hardness

5-5.5

Mohs

Luster

Adamantine

Streak

White

Transparency

Translucent

mineralrare

Stibiotantalite

Hardness: 5-5.5
Luster: Adamantine
Streak: White
Transparency: Translucent

Is this stibiotantalite?

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 stibiotantalite with a known reference. Stibiotantalite 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. Stibiotantalite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Stibiotantalite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: yellow, brown, tan, colorless, greenish.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: prismatic, tabular, or massive.

Often confused with

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

How to tell apart: Streak differs, so Stibiotantalite leaves white, Tantalite leaves black to reddish-brown; luster reads adamantine on Stibiotantalite and submetallic to resinous on Tantalite.

How to tell apart: Luster reads adamantine on Stibiotantalite and vitreous on Scheelite.

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Often found alongside stibiotantalite

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

All properties

Chemical formula: SbTaO₄
Mohs hardness: 5-5.5
Density: 7.3-7.5 g/cm³
Colors: Yellow Brown Tan Colorless Greenish
Streak: White
Luster: Adamantine
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Prismatic, Tabular, Or Massive
Cleavage: Distinct
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites
Typical price: $50-500 per specimen depending on size and quality

Where rockhounds find stibiotantalite

Classic worldwide localities

California, USA
Brazil
Madagascar
Mozambique
Australia

Field-hunting tip

Look in granite pegmatites country, the host setting where stibiotantalite typically forms. If you start seeing quartz, albite, lepidolite in float, you are in the right ground. Field specimens usually show a prismatic, tabular, or massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify stibiotantalite?+

Mohs hardness is 5-5.5. It typically shows a adamantine luster. The streak is white. Common colors include yellow, brown, tan, colorless.

Where is stibiotantalite found?+

Notable localities include California, USA; Brazil; Madagascar; Mozambique; Australia.

How much is stibiotantalite worth?+

Typical asking prices fall in the range of $50-500 per specimen depending on size and quality. Quality, size, and provenance can move individual specimens well outside that range.

Is stibiotantalite safe to handle?+

It contains toxic constituents. Contains antimony, which can be toxic if ingested or inhaled; wash hands thoroughly after handling and avoid grinding or creating dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like stibiotantalite?+

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

What minerals are found with stibiotantalite?+

Stibiotantalite commonly co-occurs with Quartz, Albite, Lepidolite, Tourmaline, Beryl. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does stibiotantalite form in?+

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

What is stibiotantalite used for?+

Stibiotantalite is used in collector.

Find stibiotantalite on the map

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