Sardignaite is a rare bismuth molybdate, typically pale yellow. It was approved as a distinct mineral species in 2008. It was first described from Su Senargiu, near Sarroch, Sardegna, Italy.

Hardness

3.5-4

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrare

Sardignaite

Sardignaite is a rare bismuth molybdate, typically pale yellow. It was approved as a distinct mineral species in 2008. It was first described from Su Senargiu, near Sarroch, Sardegna, Italy.

Hardness: 3.5-4
Luster: Adamantine
Streak: White
Transparency: Transparent

No image

Is this sardignaite?

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 sardignaite with a known reference. Sardignaite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Sardignaite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Sardignaite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: pale yellow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals, crusts, aggregates.

Often confused with

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

How to tell apart: Sardignaite is noticeably harder (Mohs 3.5-4 vs. 2-2.5).

Compare →

Often found alongside sardignaite

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

All properties

Chemical formula: BiMo₂O₇(OH)·2H₂O
Mohs hardness: 3.5-4
Density: 4.82 g/cm³
Colors: Pale Yellow
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Crusts, Aggregates
Cleavage: Distinct
Rarity: Rare
Uses: Collector
Host rock: Oxidized Lead-zinc Ore Deposits

Where rockhounds find sardignaite

Classic worldwide localities

Sa Duchessa Mine, Sardinia, Italy

Field-hunting tip

Look in oxidized lead-zinc ore deposits country, the host setting where sardignaite typically forms. If you start seeing cerussite, anglesite, galena in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sardignaite?+

Mohs hardness is 3.5-4. It typically shows a adamantine luster. The streak is white. Common colors include pale yellow.

Where is sardignaite found?+

Notable localities include Sa Duchessa Mine, Sardinia, Italy.

Is sardignaite safe to handle?+

It contains toxic constituents. Contains bismuth, 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 sardignaite?+

Sardignaite is most often confused with Anglesite, Cerussite, Lanarkite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with sardignaite?+

Sardignaite commonly co-occurs with Cerussite, Anglesite, Galena, Phosgenite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sardignaite form in?+

Sardignaite typically forms in oxidized lead-zinc ore deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sardignaite used for?+

Sardignaite is used in collector.

Find sardignaite on the map

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