Juanite is a rare calcium silicate mineral typically found as fibrous or lath-like aggregates in contact metamorphic rocks. It is most often identified by its characteristic pearly luster and association with other calc-silicate minerals in skarn deposits. Because of its rarity and subtle appearance, it is primarily sought after by advanced mineral collectors.
Is this juanite?
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 juanite with a known reference. Juanite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Juanite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Juanite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: fibrous aggregates, lath-like crystals.
Often confused with
Juanite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Pectolite is the harder of the two (Mohs 4.5-5 vs. 3.5); luster reads pearly on Juanite and vitreous to silky on Pectolite.
How to tell apart: Wollastonite is the harder of the two (Mohs 4.5-5 vs. 3.5); luster reads pearly on Juanite and vitreous on Wollastonite.
Often found alongside juanite
Minerals reported to co-occur with juanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₁₀Al₂Si₈O₂₇·4H₂O
- Mohs hardness
- 3.5
- Density
- 2.45 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Fibrous Aggregates, Lath-like Crystals
- Cleavage
- Perfect in One Direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Contact Metamorphic Zones
- Typical price
- $20-150 for small specimens
Where rockhounds find juanite
Classic worldwide localities
- New Mexico, USA
- California, USA
Field-hunting tip
Look in contact metamorphic zones country — that is the host setting where juanite typically forms. If you start seeing calcite, vesuvianite, diopside in float, you are in the right ground. Field specimens usually show a fibrous aggregates, lath-like crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find juanite on the map
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