Lucchesiite is a rare member of the tourmaline group, chemically defined as a calcium-dominant analogue of schorl. It typically presents as black prismatic crystals within granitic pegmatites and is often visually indistinguishable from more common tourmaline species without chemical analysis.

Hardness

Mohs

Luster

Vitreous

Streak

Gray

Transparency

Transparent

mineralrareTourmaline Group family

Lucchesiite

Hardness: ~7
Luster: Vitreous
Streak: Gray
Transparency: Transparent

Is this lucchesiite?

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 lucchesiite with a known reference. Lucchesiite sits at Mohs ~7, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: gray.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: black.
5
Look at form & habit
Crystal system: trigonal. Typical habit: prismatic crystals.

Often confused with

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

mineral

Schorl

Mohs 7

How to tell apart: Streak differs, so Lucchesiite leaves gray, Schorl leaves white.

How to tell apart: Streak differs, so Lucchesiite leaves gray, Dravite leaves light brown, white.

Compare →

Often found alongside lucchesiite

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

All properties

Chemical formula: CaFe²⁺₃Al₆(Si₆O₁₈)(BO₃)₃(OH)₃O
Mohs hardness: ~7
Density: 3.209 g/cm³
Colors: Black
Streak: Gray
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Prismatic crystals
Cleavage: Poor/indistinct on {0001}
Rarity: Rare
Uses: Collector
Host rock: As graphic intergrowths, in the central parts of a contaminated anatectic pegmatite dike (Czech Republic)

Where rockhounds find lucchesiite

Classic worldwide localities

Ratnapura, Sri Lanka and Mirošov, near Strážek, western Moravia, Czech Republic

Field-hunting tip

Where it forms: As graphic intergrowths, in the central parts of a contaminated anatectic pegmatite dike (Czech Republic). If you start seeing ca-rich schorl, plagioclase, k-feldspar in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify lucchesiite?+

Mohs hardness is ~7. Luster: vitreous. The streak is gray. Common colors include black.

Where is lucchesiite found?+

Notable localities include Ratnapura, Sri Lanka and Mirošov, near Strážek, western Moravia, Czech Republic.

What rocks look like lucchesiite?+

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

What minerals are found with lucchesiite?+

Lucchesiite commonly co-occurs with Ca-rich schorl, Plagioclase, K-feldspar, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does lucchesiite form in?+

Where it forms: As graphic intergrowths, in the central parts of a contaminated anatectic pegmatite dike (Czech Republic). Working float back to the host body is the standard way to chase a fresh occurrence.

What is lucchesiite used for?+

Lucchesiite is used in collector.

Find lucchesiite on the map

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