Faujasite is a rare zeolite mineral that forms distinct, sharp octahedral crystals in cavities of volcanic rocks. It is highly valued by collectors for its geometric precision, though it is often found in very small, microscopic sizes. It typically occurs as an alteration product in phonolitic and basaltic environments.
Is this faujasite-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 faujasite-na with a known reference. Faujasite-Na sits at Mohs 4.5-5, 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 to adamantine.
- 4Match the color rangeCompare against the expected color range: white, colorless, pale brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: crystalline.
Often confused with
Faujasite-Na vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside faujasite-na
Minerals reported to co-occur with faujasite-na. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na₂,Ca,Mg)₃.₅[Al₇Si₁₇O₄₈]·32H₂O
- Mohs hardness
- 4.5-5
- Density
- 1.92-1.93 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to adamantine
- Transparency
- Transparent to translucent
- Crystal system
- Cubic
- Crystal habit
- Crystalline
- Cleavage
- {111}, perfect
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- Rare, in vesicles of basalts, phonolites, and tuffs; formed by palagonization or authigenically
Where rockhounds find faujasite-na
Classic worldwide localities
- Cima Dome, near Valley Wells, San Bernardino Co., California, and at several localities on Oahu, Hawaii, USA
- Sasbach, Kaiserstuhl, in Baden-Württemberg, Germany
- Pflasterkaute, near Eisenach, Thuringia, Germany
- Annerod, near Giessen, and at a number of localities around the Vogelsberg volcano, Hesse, Germany
- Aci Reale and Aci Castello, Sicily, Italy
- Davis Hill and Khartoum, Ontario, Canada
Field-hunting tip
Where it forms: Rare, in vesicles of basalts, phonolites, and tuffs; formed by palagonization or authigenically. If you start seeing zeolites, olivine, augite in float, you are in the right ground. Typical habit: crystalline. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify faujasite-na?+
Where is faujasite-na found?+
What rocks look like faujasite-na?+
What minerals are found with faujasite-na?+
What kind of rock does faujasite-na form in?+
What is faujasite-na used for?+
Find faujasite-na on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
