Bariopharmacosiderite is a rare secondary mineral typically found in the oxidized zones of arsenic-rich ore deposits. It forms distinct, sharp cubic crystals that are often perched on iron-oxide stained matrices, making it a sought-after piece for systematic mineral collections.

Hardness

Mohs

Luster

Vitreous

Streak

Pale yellow

Transparency

Transparent

mineralrarePharmacosiderite Group family

Bariopharmacosiderite

Hardness: 3
Luster: Vitreous
Streak: Pale yellow
Transparency: Transparent

Is this bariopharmacosiderite?

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 bariopharmacosiderite with a known reference. Bariopharmacosiderite 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: pale yellow.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: brown.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: pseudocubic crystals.

Often confused with

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

mineral

Pharmacosiderite

Mohs 2.5

How to tell apart: Streak differs, so Bariopharmacosiderite leaves pale yellow, Pharmacosiderite leaves yellowish green; luster reads vitreous on Bariopharmacosiderite and adamantine to greasy on Pharmacosiderite.

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mineral

Natropharmacosiderite

Mohs 3

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Often found alongside bariopharmacosiderite

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

All properties

Chemical formula: Ba₀.₅Fe₄(AsO₄)₃(OH)₄·5H₂O
Mohs hardness: 3
Density: 2.75 g/cm³
Colors: Brown
Streak: Pale yellow
Luster: Vitreous
Transparency: Transparent
Crystal system: Tetragonal
Crystal habit: Pseudocubic crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: oxidized arsenic-rich hydrothermal deposits

Where rockhounds find bariopharmacosiderite

Classic worldwide localities

Wheal Gorland, Cornwall, England
Schemnitz, Slovakia
Quartzite Mountain, California, USA

Field-hunting tip

Where it forms: oxidized arsenic-rich hydrothermal deposits. If you start seeing scorodite, limonite, pharmacolite in float, you are in the right ground. Typical habit: pseudocubic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify bariopharmacosiderite?+

Mohs hardness is 3. Luster: vitreous. The streak is pale yellow. Common colors include brown.

Where is bariopharmacosiderite found?+

Notable localities include Wheal Gorland, Cornwall, England; Schemnitz, Slovakia; Quartzite Mountain, California, USA.

Is bariopharmacosiderite safe to handle?+

Bariopharmacosiderite contains arsenic and calls for real care. Contains arsenic, which is toxic. Wash hands thoroughly after handling and avoid inhaling dust or powder.

What rocks look like bariopharmacosiderite?+

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

What minerals are found with bariopharmacosiderite?+

Bariopharmacosiderite commonly co-occurs with Scorodite, Limonite, Pharmacolite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does bariopharmacosiderite form in?+

Where it forms: oxidized arsenic-rich hydrothermal deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is bariopharmacosiderite used for?+

Bariopharmacosiderite is used in collector.

Find bariopharmacosiderite on the map

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