Mazzite-Na is a rare member of the zeolite group found within the vesicles of alkaline volcanic rocks. It typically forms as small, acicular to prismatic hexagonal crystals and is highly prized by collectors for its crystallography and scarcity.
Is this mazzite-na?
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 mazzite-na with a known reference. Mazzite-Na sits at Mohs 3.5-4, 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, white.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: fibrous, silky.
Often confused with
Mazzite-Na vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside mazzite-na
Minerals reported to co-occur with mazzite-na. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₈(Si₂₈Al₈)O₇₂·30H₂O
- Mohs hardness
- 3.5-4
- Density
- 2.16 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Fibrous, silky
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Filling cavities in basalt overlain by layers of silt and clay that are overlain by lacustrine deposits of silt and sodium borate with a few interbeds of rhyolite tuff
Where rockhounds find mazzite-na
Classic worldwide localities
- U.S. Borax mine, Boron, California, USA
Field-hunting tip
Where it forms: Filling cavities in basalt overlain by layers of silt and clay that are overlain by lacustrine deposits of silt and sodium borate with a few interbeds of rhyolite tuff. If you start seeing ferroan saponite, phillipsite-na, gmelinite-na in float, you are in the right ground. Typical habit: fibrous, silky. Train your eye for that shape before scanning the outcrop.







