Armenite is a rare barium-calcium cyclosilicate that typically occurs as pseudo-hexagonal prismatic crystals. It is primarily sought by advanced collectors for its complex twinning patterns and rarity in hydrothermal environments.

Hardness

7-8

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareOsumilite Group family

Armenite

Hardness: 7-8
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this armenite?

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 armenite with a known reference. Armenite sits at Mohs 7-8, 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: colorless, gray green, white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: prismatic crystals, often forming pseudo-hexagonal cyclic twins.

Often confused with

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

How to tell apart: Armenite is noticeably harder (Mohs 7-8 vs. 5-5.5); streak differs, so Armenite leaves white, Osumilite leaves blue-gray.

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Often found alongside armenite

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

All properties

Chemical formula: BaCa₂Al₆Si₉O₃₀·2H₂O
Mohs hardness: 7-8
Density: 2.74-2.76 g/cm³
Colors: Colorless Gray green White
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Prismatic crystals, often forming pseudo-hexagonal cyclic twins
Cleavage: Perfect prismatic, one pinacoidal distinct; partings along sector boundaries
Rarity: Rare
Uses: Collector
Host rock: In calcite veins (Kongsberg, Norway); in manganese-metasomatized diorite included in later granodiorite (Rémigny, Canada)

Where rockhounds find armenite

Classic worldwide localities

Armen mine, near Kongsberg, Norway
Su Zurfuru mine, Fluminese, Sardinia, Italy
Wasenalp, near Simplon, Valais, Switzerland
Coire Loch Kander, 11 km south-southeast of Braemar, Scotland
Chvaletice, Czech Republic
Rémigny, Quebec, Canada

Field-hunting tip

Where it forms: In calcite veins (Kongsberg, Norway); in manganese-metasomatized diorite included in later granodiorite (Rémigny, Canada). If you start seeing axinite, pyrrhotite, quartz in float, you are in the right ground. Typical habit: prismatic crystals, often forming pseudo-hexagonal cyclic twins. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify armenite?+

Mohs hardness is 7-8. Luster: vitreous. The streak is white. Common colors include colorless, gray green, white.

Where is armenite found?+

Notable localities include Armen mine, near Kongsberg, Norway; Su Zurfuru mine, Fluminese, Sardinia, Italy; Wasenalp, near Simplon, Valais, Switzerland; Coire Loch Kander, 11 km south-southeast of Braemar, Scotland; Chvaletice, Czech Republic.

What rocks look like armenite?+

Armenite is most often confused with Beryl, Cordierite, Osumilite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with armenite?+

Armenite commonly co-occurs with Axinite, Pyrrhotite, Quartz, Albite, Manganiferous zoisite, Piemontite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does armenite form in?+

Where it forms: In calcite veins (Kongsberg, Norway); in manganese-metasomatized diorite included in later granodiorite (Rémigny, Canada). Working float back to the host body is the standard way to chase a fresh occurrence.

What is armenite used for?+

Armenite is used in collector.

Find armenite on the map

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