Rosiaite is a very rare lead-antimony oxide mineral originally discovered in the gold-mining district of Rosia Montana, Romania. It typically forms small, distinct yellow crystals associated with other secondary lead minerals and gold-bearing ores.

Hardness

5.5

Mohs

Luster

Resinous

Streak

White

Transparency

Transparent

mineralrarePyrochlore Supergroup family

Rosiaite

Hardness: 5.5
Luster: Resinous
Streak: White
Transparency: Transparent

Is this rosiaite?

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 rosiaite with a known reference. Rosiaite sits at Mohs 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. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: resinous.
4
Match the color range
Compare against the expected color range: colorless, light yellow.
5
Look at form & habit
Crystal system: trigonal. Typical habit: tabular to rhombohedral crystals.

Often confused with

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

mineral

Bindheimite

Mohs 4-4.5

How to tell apart: Rosiaite is noticeably harder (Mohs 5.5 vs. 4-4.5).

Compare →

Often found alongside rosiaite

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

All properties

Chemical formula: PbSb₂O₆
Mohs hardness: 5.5
Density: 6.96 g/cm³
Colors: Colorless Light yellow
Streak: White
Luster: Resinous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Tabular to rhombohedral crystals
Cleavage: {0001}, parting, possible
Rarity: Rare
Uses: Collector
Host rock: From an antimony deposit in highly silicified evaporites (Cetine mine, Italy)

Where rockhounds find rosiaite

Classic worldwide localities

Cetine mine, 20 km southwest of Siena, and the Tafone mine, Grosseto, Tuscany, Italy

Field-hunting tip

Where it forms: From an antimony deposit in highly silicified evaporites (Cetine mine, Italy). If you start seeing valentinite, tripuhyite, bindheimite in float, you are in the right ground. Typical habit: tabular to rhombohedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify rosiaite?+

Mohs hardness is 5.5. Luster: resinous. The streak is white. Common colors include colorless, light yellow.

Where is rosiaite found?+

Notable localities include Cetine mine, 20 km southwest of Siena, and the Tafone mine, Grosseto, Tuscany, Italy.

Is rosiaite safe to handle?+

Rosiaite contains antimony and lead. Contains lead and antimony; wash hands thoroughly after handling and avoid inhaling dust.

What rocks look like rosiaite?+

Rosiaite is most often confused with Bindheimite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with rosiaite?+

Rosiaite commonly co-occurs with Valentinite, Tripuhyite, Bindheimite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does rosiaite form in?+

Where it forms: From an antimony deposit in highly silicified evaporites (Cetine mine, Italy). Working float back to the host body is the standard way to chase a fresh occurrence.

What is rosiaite used for?+

Rosiaite is used in collector.

Find rosiaite on the map

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