Capranicaite is a rare phyllosilicate mineral discovered within volcanic ejecta in the Viterbo region of Italy. It typically forms as small, thin, tabular crystals often associated with various zeolite minerals and calcite in vugs.
Is this capranicaite?
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 capranicaite with a known reference. Capranicaite sits at Mohs <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: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals.
Often confused with
Capranicaite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside capranicaite
Minerals reported to co-occur with capranicaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KCaNaAl₄B₄Si₂O₁₈
- Mohs hardness
- <6
- Density
- 2.41 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals
- Cleavage
- Good on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage metasomatic product inside miarolitic cavities in a block of feldspathoid-bearing syenite in an ignimbrite unit ejected from a complex volcano
Where rockhounds find capranicaite
Classic worldwide localities
- Vico volcanic complex, Capranica, Latium, Viterbo province, Italy
Field-hunting tip
Where it forms: A late-stage metasomatic product inside miarolitic cavities in a block of feldspathoid-bearing syenite in an ignimbrite unit ejected from a complex volcano. If you start seeing k-feldspars, plagioclase, andradite 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 capranicaite?+
Where is capranicaite found?+
What rocks look like capranicaite?+
What minerals are found with capranicaite?+
What kind of rock does capranicaite form in?+
What is capranicaite used for?+
Find capranicaite on the map
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