Ramaccioniite is a rare copper selenate. It was approved as a distinct mineral species in 2018. It was first described from Mina San Pedro, Vinchina Department, La Rioja Province, Argentina.

Hardness

2-3

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Translucent

mineralrare

Ramaccioniite

Ramaccioniite is a rare copper selenate. It was approved as a distinct mineral species in 2018. It was first described from Mina San Pedro, Vinchina Department, La Rioja Province, Argentina.

Hardness: 2-3
Luster: Pearly
Streak: Yellow
Transparency: Translucent

Is this ramaccioniite?

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

Often confused with

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

mineral

Gypsum

Mohs 2

How to tell apart: Streak differs, so Ramaccioniite leaves yellow, Gypsum leaves white; luster reads pearly on Ramaccioniite and vitreous on Gypsum.

How to tell apart: Streak differs, so Ramaccioniite leaves yellow, Anhydrite leaves white; luster reads pearly on Ramaccioniite and vitreous on Anhydrite.

Compare →

Often found alongside ramaccioniite

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

All properties

Chemical formula: Cu₄[SeO₄](OH)₆
Mohs hardness: 2-3
Colors: Yellow Yellow-green
Streak: Yellow
Luster: Pearly
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Platy Crystals, Crusts, Or Globular Aggregates
Cleavage: Perfect in One Direction
Rarity: Rare
Uses: Collector
Host rock: Evaporite Deposits

Where rockhounds find ramaccioniite

Classic worldwide localities

Mina San Pedro, La Rioja Province, Argentina

Field-hunting tip

Look in evaporite deposits country, the host setting where ramaccioniite typically forms. If you start seeing halite, glauberite, gypsum in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, or globular aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ramaccioniite?+

Mohs hardness is 2-3. It typically shows a pearly luster. The streak is yellow. Common colors include yellow, yellow-green.

Where is ramaccioniite found?+

Notable localities include Mina San Pedro, La Rioja Province, Argentina.

Is ramaccioniite safe to handle?+

It contains toxic constituents. Contains selenium, 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 ramaccioniite?+

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

What minerals are found with ramaccioniite?+

Ramaccioniite commonly co-occurs with Halite, Glauberite, Gypsum. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ramaccioniite form in?+

Ramaccioniite typically forms in evaporite deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ramaccioniite used for?+

Ramaccioniite is used in collector.

Find ramaccioniite on the map

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