Umbrianite is an exceptionally rare sodium silicate mineral found primarily within the ejecta of the Somma-Vesuvius volcanic complex. Collectors usually encounter it as small, colorless to pale yellow tabular crystals embedded in volcanic matrices.
Is this umbrianite?
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 umbrianite with a known reference. Umbrianite sits at Mohs ~5, 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: colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals.
Often confused with
Umbrianite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside umbrianite
Minerals reported to co-occur with umbrianite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₇Na₂Ca₂[Al₃Si₁₀O₂₉]F₂Cl₂
- Mohs hardness
- ~5
- Density
- 2.49 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular crystals
- Cleavage
- Perfect on (010), distinct on (100) and (001)
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Essential groundmass, late-magmatic mineral in vesicular melilitolite, unstable under post-magmatic hydrothermal conditions and alters to Ba-rich hydrated phases
Where rockhounds find umbrianite
Classic worldwide localities
- Pian di Celle volcano, Umbria, Italy
Field-hunting tip
Where it forms: Essential groundmass, late-magmatic mineral in vesicular melilitolite, unstable under post-magmatic hydrothermal conditions and alters to Ba-rich hydrated phases. If you start seeing kalsilite, leucite, fluorophlogopite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify umbrianite?+
Where is umbrianite found?+
What rocks look like umbrianite?+
What minerals are found with umbrianite?+
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What is umbrianite used for?+
Find umbrianite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
