Alloriite is a rare member of the cancrinite group of minerals, typically found in alkaline igneous complexes. It forms small, prismatic to tabular crystals that are difficult to distinguish from other cancrinite-group members without advanced chemical analysis.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareCancrinite Group family

Alloriite

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this alloriite?

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 alloriite with a known reference. Alloriite sits at Mohs 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: trigonal. Typical habit: prismatic, tabular.

Often confused with

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

Often found alongside alloriite

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

All properties

Chemical formula: (Na,K,Ca)₂₄(Na,Ca)₄Ca₄(Si,Al)₄₈O₉₆(SO₄)₄(SO₃,CO₃)₂(OH,Cl)₂(H₂O,OH)₄
Mohs hardness: 5
Density: 2.35 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Prismatic, tabular
Cleavage: Imperfect on {101̄0}
Rarity: Rare
Uses: Collector
Host rock: Lining the walls of small miarolitic cavities in a sanidine-syenite volcanic bomb

Where rockhounds find alloriite

Classic worldwide localities

Mt. Cavalluccio, Campagnano di Roma, Sacrofano caldera, Rome Province, Latium, Italy

Field-hunting tip

Where it forms: Lining the walls of small miarolitic cavities in a sanidine-syenite volcanic bomb. If you start seeing sanidine, biotite, andradite in float, you are in the right ground. Typical habit: prismatic, tabular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify alloriite?+

Mohs hardness is 5. Luster: vitreous. The streak is white. Common colors include colorless.

Where is alloriite found?+

Notable localities include Mt. Cavalluccio, Campagnano di Roma, Sacrofano caldera, Rome Province, Latium, Italy.

What rocks look like alloriite?+

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

What minerals are found with alloriite?+

Alloriite commonly co-occurs with Sanidine, Biotite, Andradite, Apatite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does alloriite form in?+

Where it forms: Lining the walls of small miarolitic cavities in a sanidine-syenite volcanic bomb. Working float back to the host body is the standard way to chase a fresh occurrence.

What is alloriite used for?+

Alloriite is used in collector.

Find alloriite on the map

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