Akaogiite is a rare monoclinic polymorph of titanium dioxide that forms as a high-pressure alteration product. It is primarily found as microscopic inclusions or thin platy crystals within granite pegmatites and is scientifically significant for its unique structural arrangement compared to more common TiO₂ polymorphs.

Hardness

Mohs

Transparency

Opaque

mineralrareAnatase family

Akaogiite

Hardness: 6
Transparency: Opaque

No image

Is this akaogiite?

3-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 akaogiite with a known reference. Akaogiite sits at Mohs 6, softer than the next harder reference, harder than the previous one.
2
Match the color range
Compare against the expected color range: black, brown.
3
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals.

Often confused with

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

Often found alongside akaogiite

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

All properties

Chemical formula: TiO₂
Mohs hardness: 6
Density: 4.72 g/cm³
Colors: Black Brown
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Platy crystals
Rarity: Rare
Uses: Collector
Host rock: Within multiphase TiO2 clusters enclosed in biotite in heavily shocked garnet-cordierite-sillimanite gneiss in the breccia of a meteorite impact crater

Where rockhounds find akaogiite

Classic worldwide localities

Ries meteorite impact crater, Germany

Field-hunting tip

Where it forms: Within multiphase TiO2 clusters enclosed in biotite in heavily shocked garnet-cordierite-sillimanite gneiss in the breccia of a meteorite impact crater. If you start seeing rutile, ilmenite, titanite in float, you are in the right ground. Typical habit: platy crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify akaogiite?+

Mohs hardness is 6. Common colors include black, brown.

Where is akaogiite found?+

Notable localities include Ries meteorite impact crater, Germany.

What rocks look like akaogiite?+

Akaogiite is most often confused with Anatase, Rutile, Brookite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with akaogiite?+

Akaogiite commonly co-occurs with Rutile, Ilmenite, Titanite, Graphite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does akaogiite form in?+

Where it forms: Within multiphase TiO2 clusters enclosed in biotite in heavily shocked garnet-cordierite-sillimanite gneiss in the breccia of a meteorite impact crater. Working float back to the host body is the standard way to chase a fresh occurrence.

What is akaogiite used for?+

Akaogiite is used in collector.

Find akaogiite on the map

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