Camgasite is a very rare hydrated calcium magnesium arsenate that typically forms delicate, radiating clusters of acicular crystals. It is primarily found in the oxidized zones of arsenic-rich base metal deposits, notably in the historic mining district of Lavrion, Greece. Due to its arsenic content and limited occurrence, it is highly sought after by systematic mineral collectors.

Hardness

3-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Camgasite

Hardness: 3-4
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this camgasite?

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 camgasite with a known reference. Camgasite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Camgasite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Camgasite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, colorless.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: acicular crystals, radiating sprays.

Often confused with

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

mineral

Picropharmacolite

Mohs 2.5

How to tell apart: Luster reads vitreous on Camgasite and silky on Picropharmacolite.

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Often found alongside camgasite

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

All properties

Chemical formula: CaMg(AsO₄)(OH)·5H₂O
Mohs hardness: 3-4
Density: 2.98 g/cm³
Colors: White Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Acicular Crystals, Radiating Sprays
Cleavage: Perfect On {010}
Rarity: Rare
Uses: Collector
Host rock: Oxidized Arsenic-rich Hydrothermal Base-metal Deposits
Typical price: $50-300 per specimen

Where rockhounds find camgasite

Classic worldwide localities

Kamareza mines, Lavrion, Greece

Field-hunting tip

Look in oxidized arsenic-rich hydrothermal base-metal deposits country — that is the host setting where camgasite typically forms. If you start seeing arseniosiderite, farmaccosiderite, goethite in float, you are in the right ground. Field specimens usually show a acicular crystals, radiating sprays habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify camgasite?+

Mohs hardness is 3-4. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless.

Where is camgasite found?+

Notable localities include Kamareza mines, Lavrion, Greece.

How much is camgasite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is camgasite safe to handle?+

It contains toxic constituents. Contains arsenic. Handle with care, wash hands after touching, and avoid inhalation of dust or ingestion. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like camgasite?+

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

What minerals are found with camgasite?+

Camgasite commonly co-occurs with Arseniosiderite, Farmaccosiderite, Goethite, Annabergite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does camgasite form in?+

Camgasite typically forms in oxidized arsenic-rich hydrothermal base-metal deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is camgasite used for?+

Camgasite is used in collector.

Find camgasite on the map

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