Wadalite is a rare calcium-aluminum silicate chloride mineral typically occurring as small, transparent dodecahedral crystals. It is primarily found in contact-metamorphosed limestone xenoliths within volcanic rocks, often requiring microscopic study for positive identification.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareMayenite Supergroup family

Wadalite

Hardness: 6
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this wadalite?

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 wadalite with a known reference. Wadalite sits at Mohs 6, 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: cubic. Typical habit: dodecahedral crystals.

Often confused with

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

Often found alongside wadalite

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

All properties

Chemical formula: Ca₆Al₅Si₂O₁₆Cl₃
Mohs hardness: 6
Density: 3.06 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Dodecahedral crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Skarn xenolith in two-pyroxene andesite

Where rockhounds find wadalite

Classic worldwide localities

Tadano, Koriyama Cith, Fukushima Prefecture, Japan (type locality)

Field-hunting tip

Where it forms: Skarn xenolith in two-pyroxene andesite. If you start seeing gehlenite, spinell, perovskite in float, you are in the right ground. Typical habit: dodecahedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify wadalite?+

Mohs hardness is 6. Luster: vitreous. The streak is white. Common colors include colorless.

Where is wadalite found?+

Notable localities include Tadano, Koriyama Cith, Fukushima Prefecture, Japan (type locality).

What rocks look like wadalite?+

Wadalite is most often confused with Grossular. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with wadalite?+

Wadalite commonly co-occurs with Gehlenite, Spinell, Perovskite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does wadalite form in?+

Where it forms: Skarn xenolith in two-pyroxene andesite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is wadalite used for?+

Wadalite is used in collector.

Find wadalite on the map

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