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 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: dull.
- 4Match the color rangeCompare against the expected color range: white, pistachio green, brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: fibrous.
Often confused with
Juanite vs. its common look-alikes, and how to tell them apart in the field.
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
- Ca₁₀(Mg,Fe)₄(Si,Al)₁₃(O,OH)₃₉·4H₂O
- Mohs hardness
- 5.5
- Density
- 3.01-3.3 g/cm³
- Streak
- White
- Luster
- Dull
- Transparency
- Semitransparent
- Crystal system
- Orthorhombic
- Crystal habit
- Fibrous
- Cleavage
- Perfect in one direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed by hydrothermal alteration of a coarse-grained melilite rock (uncompahgrite) previously subjected to deuteric alteration (Iron Hill, Colorado, USA)
Where rockhounds find juanite
Classic worldwide localities
- Iron Hill carbonatite, Powderhorn-Cebolla district, Gunnison Co., Colorado, USA
- Kiya-Shaltyrsk massif, Kuznetsk, Ala-Tau Range, Tien Shan, Kazakhstan
- Kovdor massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: Formed by hydrothermal alteration of a coarse-grained melilite rock (uncompahgrite) previously subjected to deuteric alteration (Iron Hill, Colorado, USA). If you start seeing perovskite, phlogopite, magnetite in float, you are in the right ground. Typical habit: fibrous. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify juanite?+
Where is juanite found?+
What rocks look like juanite?+
What minerals are found with juanite?+
What kind of rock does juanite form in?+
What is juanite used for?+
Find juanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
