Avogadrite is a rare potassium fluoroborate mineral primarily found as a sublimation product in volcanic fumaroles. It typically occurs as tiny, colorless to white tabular crystals or crusts, often associated with other rare volcanic halides.
Is this avogadrite?
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 avogadrite with a known reference. Avogadrite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: colorless.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to greasy.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellowish, reddish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular.
Often confused with
Avogadrite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside avogadrite
Minerals reported to co-occur with avogadrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KBF₄
- Mohs hardness
- 2.5
- Density
- 2.62 g/cm³
- Streak
- Colorless
- Luster
- Vitreous to greasy
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular
- Cleavage
- Poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed as a sublimation product around volcanic fumaroles
Where rockhounds find avogadrite
Classic worldwide localities
- Vesuvius, Campania, and on Vulcano, Lipari Islands, Italy
- Volcanoes on the Kamchatka Peninsula, Russia
Field-hunting tip
Where it forms: Formed as a sublimation product around volcanic fumaroles. If you start seeing sassolite, malladrite, hieratite in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify avogadrite?+
Where is avogadrite found?+
Is avogadrite safe to handle?+
What rocks look like avogadrite?+
What minerals are found with avogadrite?+
What kind of rock does avogadrite form in?+
What is avogadrite used for?+
Find avogadrite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
