Latiumite is an extremely rare silicate mineral typically found in volcanic ejecta or contact metamorphic zones. It usually occurs as small, pale tabular crystals or granular inclusions within igneous complexes, most notably in the Alban Hills of Italy.

Hardness

5.5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrare

Latiumite

Hardness: 5.5-6
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

Is this latiumite?

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 latiumite with a known reference. Latiumite sits at Mohs 5.5-6, 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: white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: massive, tabular.

Often confused with

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

Often found alongside latiumite

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

All properties

Chemical formula: (Ca,K)₄(Si,Al)₅O₁₁(SO₄,CO₃)
Mohs hardness: 5.5-6
Density: 2.93 g/cm³
Colors: White
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Monoclinic
Crystal habit: Massive, tabular
Cleavage: {100}, perfect
Rarity: Rare
Uses: Collector
Host rock: In blocks of metamorphosed limestone ejected by volcanism

Where rockhounds find latiumite

Classic worldwide localities

Albano, in the Alban Hills, Lazio, and from Pitigliano, near Grosseto, Tuscany, Italy

Field-hunting tip

Where it forms: In blocks of metamorphosed limestone ejected by volcanism. If you start seeing hedenbergite, grossular-andradite, melilite in float, you are in the right ground. Typical habit: massive, tabular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify latiumite?+

Mohs hardness is 5.5-6. Luster: vitreous. The streak is white. Common colors include white.

Where is latiumite found?+

Notable localities include Albano, in the Alban Hills, Lazio, and from Pitigliano, near Grosseto, Tuscany, Italy.

What rocks look like latiumite?+

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

What minerals are found with latiumite?+

Latiumite commonly co-occurs with Hedenbergite, Grossular-andradite, Melilite, Leucite, Haüyne, Kaliophilite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does latiumite form in?+

Where it forms: In blocks of metamorphosed limestone ejected by volcanism. Working float back to the host body is the standard way to chase a fresh occurrence.

What is latiumite used for?+

Latiumite is used in collector.

Find latiumite on the map

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