Davyne is a rare member of the cancrinite group, primarily found as prismatic crystals or granular masses within alkaline volcanic rocks. It is most famous for its occurrence in the ejecta of Mount Vesuvius, where it forms in association with other feldspathoid minerals. Collectors should look for its distinctive hexagonal symmetry and association with the silica-undersaturated volcanic environments.
Is this davyne?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch davyne with a known reference. Davyne sits at Mohs 5.5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: hexagonal, prismatic.
Often confused with
Davyne vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside davyne
Minerals reported to co-occur with davyne. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,K)₆Ca₂(Si₆Al₆)O₂₄Cl₃(SO₄)₀.₅
- Mohs hardness
- 5.5-6
- Density
- 2.42-2.53 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Hexagonal
- Crystal habit
- Hexagonal, prismatic
- Cleavage
- Perfect on {1010}, perfect to indistinct on {0001}
- Rarity
- Rare
- Uses
- Collector, Research
- Host rock
- In volcanic ejecta and in leucite-rich lavas
Where rockhounds find davyne
Classic worldwide localities
- Monte Somma and Vesuvius, Campania, and Pitigliano, Tuscany, Italy
- Island of Zabargad (Zabirget or St. Johns), in the Red Sea, Egypt
- Mt. Karnasurt, Lovozero massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: In volcanic ejecta and in leucite-rich lavas. If you start seeing nepheline, leucite in float, you are in the right ground. Typical habit: hexagonal, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify davyne?+
Where is davyne found?+
What rocks look like davyne?+
What minerals are found with davyne?+
What kind of rock does davyne form in?+
What is davyne used for?+
Find davyne on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
