Biachellaite is a rare member of the cancrinite group typically found as prismatic crystals in volcanic ejecta blocks. It is structurally complex and usually identified through micro-analysis, often appearing as tiny, clear to pale blue inclusions within host rock matrices.
Is this biachellaite?
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 biachellaite with a known reference. Biachellaite 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: trigonal. Typical habit: prismatic crystals.
Often confused with
Biachellaite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside biachellaite
Minerals reported to co-occur with biachellaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,Ca,K)₈(Si₆Al₆O₂₄)(SO₄)₂(OH)₀.₅·H₂O
- Mohs hardness
- 5
- Density
- 2.51 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Prismatic crystals
- Cleavage
- Perfect on {101̄0}, imperfect (parting?) on {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Found in cavities in volcanic ejecta
Where rockhounds find biachellaite
Classic worldwide localities
- Biachella Valley, Sacrofano Caldera, Sacrofano municipality, Rome province, Latium region, Italy
Field-hunting tip
Where it forms: Found in cavities in volcanic ejecta. If you start seeing sanidine, diopside, andradite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify biachellaite?+
Where is biachellaite found?+
What rocks look like biachellaite?+
What minerals are found with biachellaite?+
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What is biachellaite used for?+
Find biachellaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
