Stoppaniite is a rare iron-rich member of the beryl group characterized by its distinct blue color. It typically forms as small, transparent prismatic crystals within cavities in evolved granite pegmatites.
Is this stoppaniite?
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 stoppaniite with a known reference. Stoppaniite sits at Mohs 7.5, 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: light blue.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: euhedral crystals, prismatic.
Often confused with
Stoppaniite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside stoppaniite
Minerals reported to co-occur with stoppaniite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Be₃Fe₂(Si₆O₁₈)
- Mohs hardness
- 7.5
- Density
- 2.79 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Euhedral crystals, prismatic
- Cleavage
- Parting on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In miarolitic cavities in syenitic volcanic ejecta
Where rockhounds find stoppaniite
Classic worldwide localities
- Capranica, Vico volcanic complex, Latium, Italy
Field-hunting tip
Where it forms: In miarolitic cavities in syenitic volcanic ejecta. If you start seeing biotite, quartz, sanidine in float, you are in the right ground. Typical habit: euhedral crystals, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify stoppaniite?+
Where is stoppaniite found?+
Is stoppaniite safe to handle?+
What rocks look like stoppaniite?+
What minerals are found with stoppaniite?+
What kind of rock does stoppaniite form in?+
What is stoppaniite used for?+
Find stoppaniite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
