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, 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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