Achyrophanite is a historical term for a variety of iron-rich garnet, often associated with the almandine-spessartine series. It typically forms as granular or poorly defined dodecahedral crystals in metamorphic environments and is primarily sought by systematic mineral collectors.

Hardness

6.5-7.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareGarnet Group family

Achyrophanite

Hardness: 6.5-7.5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this achyrophanite?

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 achyrophanite with a known reference. Achyrophanite sits at Mohs 6.5-7.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Achyrophanite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Achyrophanite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: dark brown, brownish-red.
5
Look at form & habit
Crystal system: cubic. Typical habit: dodecahedral crystals.

Often confused with

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

Often found alongside achyrophanite

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

All properties

Chemical formula: (Fe,Mg,Mn)₃Al₂(SiO₄)₃
Mohs hardness: 6.5-7.5
Density: 3.8-4.1 g/cm³
Colors: Dark Brown Brownish-red
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Cubic
Crystal habit: Dodecahedral Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Metamorphic Rocks
Typical price: $20-150 per specimen

Where rockhounds find achyrophanite

Classic worldwide localities

Norway
Sweden
Czech Republic

Field-hunting tip

Look in metamorphic rocks country, the host setting where achyrophanite typically forms. If you start seeing quartz, biotite, feldspar in float, you are in the right ground. Field specimens usually show a dodecahedral crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify achyrophanite?+

Mohs hardness is 6.5-7.5. It typically shows a vitreous luster. The streak is white. Common colors include dark brown, brownish-red.

Where is achyrophanite found?+

Notable localities include Norway; Sweden; Czech Republic.

How much is achyrophanite worth?+

Typical asking prices fall in the range of $20-150 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like achyrophanite?+

Achyrophanite is most often confused with Almandite, Spessartine, Andradite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with achyrophanite?+

Achyrophanite commonly co-occurs with Quartz, Biotite, Feldspar. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does achyrophanite form in?+

Achyrophanite typically forms in metamorphic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is achyrophanite used for?+

Achyrophanite is used in collector.

Find achyrophanite on the map

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