Abuite is a very rare phosphate mineral first described from the pegmatites of Mount Abu in India. It typically forms colorless to white tabular crystals that are difficult to distinguish from associated phosphate minerals without analytical testing. Collectors generally find it as a micromount specimen due to its extreme scarcity.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Abuite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this abuite?

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 abuite with a known reference. Abuite sits at Mohs 3.5, 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.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, subparallel aggregates.

Often confused with

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

mineral

Amblygonite

Mohs 5.5-6

How to tell apart: Amblygonite is the harder of the two (Mohs 5.5-6 vs. 3.5).

How to tell apart: Montebrasite is the harder of the two (Mohs 5.5-6 vs. 3.5).

Compare →

Often found alongside abuite

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

All properties

Chemical formula: CaAl₂(PO₄)₂F₂
Mohs hardness: 3.5
Density: 3.214 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals, subparallel aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In hydrothermally altered, felsic pyroclastic rocks, related to a biotite adamellite intrusion

Where rockhounds find abuite

Classic worldwide localities

Hinomaru-Nago mine, Kiyo area, Abu, Abu County, Yamaguchi Prefecture, Japan

Field-hunting tip

Where it forms: In hydrothermally altered, felsic pyroclastic rocks, related to a biotite adamellite intrusion. If you start seeing quartz, augelite, apatite in float, you are in the right ground. Typical habit: tabular crystals, subparallel aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify abuite?+

Mohs hardness is 3.5. Luster: vitreous. The streak is white. Common colors include colorless.

Where is abuite found?+

Notable localities include Hinomaru-Nago mine, Kiyo area, Abu, Abu County, Yamaguchi Prefecture, Japan.

What rocks look like abuite?+

Abuite is most often confused with Amblygonite, Montebrasite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with abuite?+

Abuite commonly co-occurs with Quartz, Augelite, Apatite, Crandallite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does abuite form in?+

Where it forms: In hydrothermally altered, felsic pyroclastic rocks, related to a biotite adamellite intrusion. Working float back to the host body is the standard way to chase a fresh occurrence.

What is abuite used for?+

Abuite is used in collector.

Find abuite on the map

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