Direnzoite is an extremely rare member of the zeolite group found in specific volcanic environments. It typically occurs as small tabular crystals associated with other zeolites and calcite in vesicle-filled cavities.

Hardness

4.5

Mohs

Luster

Vitreous to silky

Streak

White

Transparency

Translucent to transparent

mineralrareZeolite Group family

Direnzoite

Hardness: 4.5
Luster: Vitreous to silky
Streak: White
Transparency: Translucent to transparent

No image

Is this direnzoite?

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 direnzoite with a known reference. Direnzoite sits at Mohs 4.5, 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 to silky.
4
Match the color range
Compare against the expected color range: white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: fibrous, radial.

Often confused with

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

Often found alongside direnzoite

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

All properties

Chemical formula: NaK₆MgCa₂(Al₁₃Si₄₇)O₁₂₀·36H₂O
Mohs hardness: 4.5
Density: 2.12 g/cm³
Colors: White
Streak: White
Luster: Vitreous to silky
Transparency: Translucent to transparent
Crystal system: Orthorhombic
Crystal habit: Fibrous, radial
Cleavage: Distinct along [010]
Rarity: Rare
Uses: Collector
Host rock: Formed by hydrothermal crystallization in the vugs of a highly porphyritic basalt xenolith

Where rockhounds find direnzoite

Classic worldwide localities

Mont Peylenc, near St. Pierre Eynac, Massif Central, France

Field-hunting tip

Where it forms: Formed by hydrothermal crystallization in the vugs of a highly porphyritic basalt xenolith. If you start seeing mordenite, phillipsite, merlinoite in float, you are in the right ground. Typical habit: fibrous, radial. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify direnzoite?+

Mohs hardness is 4.5. Luster: vitreous to silky. The streak is white. Common colors include white.

Where is direnzoite found?+

Notable localities include Mont Peylenc, near St. Pierre Eynac, Massif Central, France.

What rocks look like direnzoite?+

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

What minerals are found with direnzoite?+

Direnzoite commonly co-occurs with Mordenite, Phillipsite, Merlinoite, Erionite, Analcime, Chabazite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does direnzoite form in?+

Where it forms: Formed by hydrothermal crystallization in the vugs of a highly porphyritic basalt xenolith. Working float back to the host body is the standard way to chase a fresh occurrence.

What is direnzoite used for?+

Direnzoite is used in collector.

Find direnzoite on the map

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