Rruffite is a rare secondary mineral typically found in the oxidized zones of arsenic-rich hydrothermal deposits. It is most notable for its distinct pink to rose-red prismatic crystals that resemble other members of the roselite group.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareRoselite Group family

Rruffite

Hardness: ~3
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this rruffite?

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 rruffite with a known reference. Rruffite sits at Mohs ~3, 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: vitreous.
4
Match the color range
Compare against the expected color range: pale.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: short prismatic to pseudo-octahedral crystals.

Often confused with

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

mineral

Roselite

Mohs 3.5

How to tell apart: Streak differs, so Rruffite leaves white, Roselite leaves light red.

How to tell apart: Streak differs, so Rruffite leaves white, Wendwilsonite leaves pale pink.

Compare →

Often found alongside rruffite

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

All properties

Chemical formula: Ca₂Cu(AsO₄)₂·2H₂O
Mohs hardness: ~3
Density: 3.79 g/cm³
Colors: Pale
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Short prismatic to pseudo-octahedral crystals
Cleavage: Perfect on {010}
Rarity: Rare
Uses: Collector
Host rock: Secondary mineral in the oxidation zone of a Cu-As ore deposit

Where rockhounds find rruffite

Classic worldwide localities

Maria Catalina mine, Pampa Larga district, Tierra Amarilla, Chile

Field-hunting tip

Where it forms: Secondary mineral in the oxidation zone of a Cu-As ore deposit. If you start seeing quartz, baryte, mansfieldite in float, you are in the right ground. Typical habit: short prismatic to pseudo-octahedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify rruffite?+

Mohs hardness is ~3. Luster: vitreous. The streak is white. Common colors include pale.

Where is rruffite found?+

Notable localities include Maria Catalina mine, Pampa Larga district, Tierra Amarilla, Chile.

Is rruffite safe to handle?+

Rruffite contains arsenic and copper and calls for real care. Contains arsenic and copper; avoid ingestion, inhalation of dust, or prolonged skin contact. Wash hands thoroughly after handling.

What rocks look like rruffite?+

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

What minerals are found with rruffite?+

Rruffite commonly co-occurs with Quartz, Baryte, Mansfieldite, Alumopharmacosiderite, Conichalcite, Metazeunerite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does rruffite form in?+

Where it forms: Secondary mineral in the oxidation zone of a Cu-As ore deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is rruffite used for?+

Rruffite is used in collector.

Find rruffite on the map

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