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 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Biachellaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Biachellaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale blue.
- 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,S,Cl)₂
- Mohs hardness
- 5-6
- Density
- 2.35 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Prismatic Crystals
- Cleavage
- Perfect On {1010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Volcanic Ejecta
- Typical price
- $50-300 per specimen
Where rockhounds find biachellaite
Classic worldwide localities
- Italy
- Russia
Field-hunting tip
Look in volcanic ejecta country — that is the host setting where biachellaite typically forms. If you start seeing nepheline, sanidine, augite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.




