Argandite is an exceptionally rare member of the garnet group, specifically a manganese vanadate. It is primarily found as small, yellow, dodecahedral crystals in highly specific metamorphic manganese deposits, most notably the Långban mines in Sweden.
Is this argandite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch argandite with a known reference. Argandite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale orange.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: orange.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: isolated anhedral grains.
Often confused with
Argandite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Spessartine is the harder of the two (Mohs 7-7.5 vs. 3.5-4); streak differs, so Argandite leaves pale orange, Spessartine leaves white.
How to tell apart: Andradite is the harder of the two (Mohs 6.5-7 vs. 3.5-4); streak differs, so Argandite leaves pale orange, Andradite leaves white; luster reads vitreous on Argandite and adamantine to resinous, dull on Andradite.
Often found alongside argandite
Minerals reported to co-occur with argandite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn₇(VO₄)₂(OH)₈
- Mohs hardness
- 3.5-4
- Density
- 3.71 g/cm³
- Colors
- Streak
- Pale orange
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Isolated anhedral grains
- Cleavage
- Distinct on {001}, by analogy with allactite
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a metamorphosed (upper greenschist facies) lens of synsedimentary exhalative Mn-Fe ore enriched in V relative to As in dolomitic marble
Where rockhounds find argandite
Classic worldwide localities
- Pipji glacier, Turtmann Valley, Central Alps, Switzerland
Field-hunting tip
Where it forms: In a metamorphosed (upper greenschist facies) lens of synsedimentary exhalative Mn-Fe ore enriched in V relative to As in dolomitic marble. If you start seeing pyrobelonite, reppiaite in float, you are in the right ground. Typical habit: isolated anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify argandite?+
Where is argandite found?+
Is argandite safe to handle?+
What rocks look like argandite?+
What minerals are found with argandite?+
What kind of rock does argandite form in?+
What is argandite used for?+
Find argandite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
